0001140361-24-004664 | S-1/A | XBRL Viewer

Fair Value of Financial Instruments

Note 5 — Fair Value of Financial Instruments

The Company’s financial instruments consist of cash and cash equivalents, marketable securities, and warrants.

Pursuant to the requirements of Accounting Standards Codification (“ASC”) Topic 820 “Fair Value Measurement,” the Company’s financial assets and liabilities measured at fair value on a recurring basis are classified and disclosed in one of the following three categories:

•	Level 1 — Financial instruments with unadjusted quoted prices listed on active market exchanges.

•

Level 2 — Financial instruments lacking unadjusted, quoted prices from active market exchanges, including over-the-counter traded financial instruments. The prices for the financial instruments are determined using prices for recently traded financial instruments with similar underlying terms as well as directly or indirectly observable inputs, such as interest rates and yield curves that are observable at commonly quoted intervals.

•	Level 3 — Financial instruments that are not actively traded on a market exchange. This category includes situations where there is little, if any, market activity for the financial instrument. The prices are determined using significant unobservable inputs or valuation techniques.

All cash equivalents and marketable securities are considered Level 1 measurements for all periods presented.

The available-for-sale marketable securities primarily consist of investment-grade, U.S.-dollar-denominated fixed and floating rate debt, measured at fair value on a recurring basis.

Marketable securities

$569

The fair value of the Company’s common stock warrant liability related to the investor warrants issued in the October 2022 Offering was calculated using a Monte Carlo valuation model and was classified as Level 3 in the fair value hierarchy.

The following is a roll-forward of the fair value of the Level 3 warrants:

(in thousands)
Balance at December 31, 2022			$6,868
Change in fair value			755
Balance at January 4, 2023 (revaluation date)			7,623
Warrants reclassified to equity			(7,623)
Balance at September 30, 2023			$—

Note 6—Fair Value of Financial Instruments

The Company’s financial instruments consist of cash and cash equivalents, marketable securities, and warrants.

Pursuant to the requirements of ASC Topic 820 “Fair Value Measurement,” the Company’s financial assets and liabilities measured at fair value on a recurring basis are classified and disclosed in one of the following three categories:

•	Level 1 - Financial instruments with unadjusted quoted prices listed on active market exchanges.

•

Level 2 - Financial instruments lacking unadjusted, quoted prices from active market exchanges, including over-the-counter traded financial instruments. The prices for the financial instruments are determined using prices for recently traded financial instruments with similar underlying terms as well as directly or indirectly observable inputs, such as interest rates and yield curves that are observable at commonly quoted intervals.

•	Level 3 - Financial instruments that are not actively traded on a market exchange. This category includes situations where there is little, if any, market activity for the financial instrument. The prices are determined using significant unobservable inputs or valuation techniques.

All cash equivalents and marketable securities are considered Level 1 measurements for all periods presented.

The available-for-sale marketable securities primarily consist of investment-grade, U.S. dollar-denominated fixed and floating-rate debt, measured at fair value on a recurring basis.

	2022		2021
(Dollars in thousands)	Fair Value	Level 1	Fair Value	Level 1
Marketable securities	$569	$569	$15,463	$15,463

The fair value of the Company’s common stock warrant liability related to the investor warrants issued in the October 2022 public offering, was calculated using a Monte Carlo valuation model and was classified as Level 3 in the fair value hierarchy.

The following is a roll-forward of the fair value of Level 3 warrants:

(in thousands)
October 18, 2022 warrant issuance			$18,695
Change in fair value			(11,827)
Ending balance December 31, 2022			$6,868

Fair values were calculated using the following assumptions:

	Oct. 18, 2022	Dec. 31, 2022
Risk-free interest rates, adjusted for continuous compounding	4.16%	3.97%
Term (years)	6.18	6.11
Expected volatility	141.5%	145.3%
Dates and probability of future equity raises	various	various

A significant change in the inputs used for the Monte Carlo and Black Scholes valuation models, such as the expected volatility, risk-free interest rate, or probability of future equity financings, in isolation, would result in significantly higher or lower fair value measurements. In combination, changes in these inputs could result in a significantly higher or lower fair value measurement if the input changes were to be aligned or could result in a minimally higher or lower fair value measurement if the input changes were of a compensating nature.

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

Stockholders' Equity (Q3) (Details) $ / shares in Units, $ in Thousands											3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Jun. 19, 2023 Tranches $ / shares shares	Dec. 08, 2022	Dec. 05, 2022	Oct. 18, 2022 USD ($) $ / shares shares	Sep. 17, 2021 USD ($) $ / shares shares	Mar. 19, 2021 USD ($) $ / shares shares	Mar. 23, 2020 USD ($) $ / shares shares	Jan. 28, 2020 USD ($) $ / shares shares	Mar. 12, 2019 $ / shares	Nov. 27, 2017 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) $ / shares shares	Jun. 30, 2023 $ / shares shares	Jun. 30, 2023 $ / shares shares	Sep. 30, 2023 USD ($) $ / shares shares	Sep. 30, 2022 USD ($) $ / shares	Dec. 31, 2022 $ / shares shares	Dec. 31, 2021 $ / shares shares	Oct. 31, 2022 $ / shares	Nov. 06, 2019 $ / shares	Oct. 25, 2019 $ / shares	May 30, 2019 $ / shares shares	Jul. 03, 2018 $ / shares
Class of Stock Disclosures [Abstract]
Common stock, par value (in dollars per share) \| $ / shares											$ 0.0001			$ 0.0001		$ 0.0001	$ 0.0001
Exercise price of warrants (in dollars per share) \| $ / shares												$ 0	$ 0
Preferred stock, shares outstanding (in shares)											0			0		0	0
Gross proceeds from public stock offering \| $														$ 2,108	$ 0
Reverse stock split		0.01
Number of common stock warrants converted into common stock (in shares)													660,046
Number of shares of common stock issued upon conversion of common stock warrants (in shares)													660,046
Maximum [Member]
Class of Stock Disclosures [Abstract]
Reverse stock split			0.01
Period of warrants expected to vest																4 years
January 2020 Offering [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares)								5,855,000
Exercise price of warrants (in dollars per share) \| $ / shares				$ 25			$ 900	$ 1,650							$ 250
Issuance of common stock, net (in shares)								2,015,000
Gross proceeds from public stock offering \| $								$ 9,700
Net proceeds from public stock offering \| $								$ 8,600
March 2020 Offering [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares)							1,387,000
Exercise price of warrants (in dollars per share) \| $ / shares							$ 1,118
Issuance of common stock, net (in shares)							1,387,000
Gross proceeds from public stock offering \| $							$ 1,200
Net proceeds from public stock offering \| $							$ 1,000
March 2021 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares)						37,958
Gross proceeds from public stock offering \| $						$ 20,900
Net proceeds from public stock offering \| $						$ 18,900
September 2021 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares)					40,056
Gross proceeds from public stock offering \| $					$ 10,000
Net proceeds from public stock offering \| $					$ 9,000
October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Gross proceeds from public stock offering \| $				$ 11,000
Net proceeds from public stock offering \| $				$ 9,400
At-the-Market Program [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares)											0			657,333
Gross proceeds from public stock offering \| $											$ 0			$ 2,300
Net proceeds from public stock offering \| $											$ 0			$ 2,100
Aggregate cash fee paid to underwriter or placement agent														3.00%
Warrants to Purchase Common Stock [Member]
Class of Stock Disclosures [Abstract]
Number of warrants vested (in shares)														0		0
Warrants to Purchase Common Stock [Member] \| Consultant [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares)																					33
Exercise price of warrants (in dollars per share) \| $ / shares																					$ 9,540
Supply Agreement [Member] \| Maximum [Member]
Class of Stock Disclosures [Abstract]
Period for ultrafiltration services	10 years
Supply Agreement [Member] \| DaVita Warrant [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares)	1,289,081
Common stock, par value (in dollars per share) \| $ / shares	$ 0.0001
Exercise price of warrants (in dollars per share) \| $ / shares	$ 3.2996
Number of warrants vested (in shares)														0
Number of tranches \| Tranches	4
Supply Agreement [Member] \| DaVita Warrant [Member] \| Tranche One [Member]
Class of Stock Disclosures [Abstract]
Percentage of warrants expected to vest	25.00%
Supply Agreement [Member] \| DaVita Warrant [Member] \| Tranche Two [Member]
Class of Stock Disclosures [Abstract]
Percentage of warrants expected to vest	25.00%
Period of warrants expected to vest	12 months
Supply Agreement [Member] \| DaVita Warrant [Member] \| Tranche Three [Member]
Class of Stock Disclosures [Abstract]
Percentage of warrants expected to vest	25.00%
Period of warrants expected to vest	24 months
Supply Agreement [Member] \| DaVita Warrant [Member] \| Tranche Four [Member]
Class of Stock Disclosures [Abstract]
Percentage of warrants expected to vest	25.00%
Period of warrants expected to vest	36 months
Supply Agreement [Member] \| DaVita Warrant [Member] \| Maximum [Member]
Class of Stock Disclosures [Abstract]
Warrants to be exercised for amount of shares ownership percentage in entity	19.90%
Series F Convertible Preferred Stock [Member]
Class of Stock Disclosures [Abstract]
Gross proceeds from issuance of convertible preferred stock \| $										$ 18,000
Net proceeds from issuance of convertible preferred stock \| $										$ 16,200
Conversion price (in dollars per share) \| $ / shares										$ 189,000												$ 89,040
Number of consecutive trading days considered for expiration														20 days		20 days
Number of consecutive trading days														30 days		30 days
Percentage of volume weighted average price of common stock										300.00%
Trading volume for each trading day \| $										$ 200
Preferred stock issued (in shares)										18,000	127			127		127	127
Number of shares issuable on conversion of preferred stock (in shares)										96
Preferred stock, shares outstanding (in shares)											127			127		127	127
Aggregate cash fee paid to underwriter or placement agent									8.00%
Series F Convertible Preferred Stock [Member] \| March 2019 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares									$ 15,750
Series F Convertible Preferred Stock [Member] \| October 2019 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares																				$ 4,230
Series F Convertible Preferred Stock [Member] \| November 2019 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares																			$ 2,983
Series F Convertible Preferred Stock [Member] \| January 2020 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares								$ 1,650
Exercise price of warrants (in dollars per share) \| $ / shares								$ 900
Series F Convertible Preferred Stock [Member] \| March 2020 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares							$ 900
Series F Convertible Preferred Stock [Member] \| March 2021 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares						$ 550
Exercise price of warrants (in dollars per share) \| $ / shares						$ 550
Series F Convertible Preferred Stock [Member] \| September 2021 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares					$ 250
Exercise price of warrants (in dollars per share) \| $ / shares					$ 250
Series F Convertible Preferred Stock [Member] \| October 2020 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares																		$ 250
Series F Convertible Preferred Stock [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares				$ 25											$ 250			$ 25
Series F Convertible Preferred Stock [Member] \| Warrants to Purchase Common Stock [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares)										191
Series F Convertible Preferred Stock [Member] \| Warrant Series 1 [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares)										16
Exercise price of warrants (in dollars per share) \| $ / shares										$ 189,000
Series F Convertible Preferred Stock [Member] \| Warrant Series 2 [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares)										4
Exercise price of warrants (in dollars per share) \| $ / shares										$ 189,000
Series I Preferred Stock [Member]
Class of Stock Disclosures [Abstract]
Preferred stock issued (in shares)											0			0		1,049,280	0
Preferred stock, shares outstanding (in shares)											0			0		1,049,280	0
Series I Preferred Stock [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares)				23,157,124
Number of shares in one unit (in shares)				1
Class A Unit [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares)				209,940
Common stock offering price per share (in dollars per share) \| $ / shares				$ 25
Number of shares in one unit (in shares)				1
Common stock exercise price per share (in dollars per share) \| $ / shares				$ 25
Class B Unit [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares)				23,157,124
Common stock offering price per share (in dollars per share) \| $ / shares				$ 0.25
Common stock exercise price per share (in dollars per share) \| $ / shares				$ 0
Common Stock [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares)											0	657,333				209,940	78,014
Common Stock [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares)				209,940
Number of shares in one unit (in shares)				1
Warrants [Member] \| Class A Unit [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Number of shares in one unit (in shares)				1.5
Warrants [Member] \| Class B Unit [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Number of shares in one unit (in shares)				1.5

Revenue Recognition (Q3) (Details)	3 Months Ended		9 Months Ended
Revenue Recognition (Q3) (Details)	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Abstract]
Expected timing of satisfaction, period						1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Abstract]
Expected timing of satisfaction, period					1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Abstract]
Expected timing of satisfaction, period	1 year		1 year
Sales Revenue [Member] \| Customer Concentration Risk [Member] \| Revenue Recognized over Time [Member] \| Maximum [Member]
Revenue, Performance Obligation [Abstract]
Percentage of net sales	1.00%	1.00%	1.00%	1.00%
Sales Revenue [Member] \| Customer Concentration Risk [Member] \| International [Member] \| Revenue Recognized over Time [Member] \| Maximum [Member]
Revenue, Performance Obligation [Abstract]
Percentage of net sales	5.00%	5.00%	5.00%	5.00%

Stock-Based Compensation (Q3) (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2023

Dec. 31, 2022

Classification of Stock-Based Compensation Expense

The following table presents the classification of stock-based compensation expense recognized for the periods below:

	Three months ended September 30		Nine months ended September 30
(in thousands)	2023	2022	2023	2022
Selling, general and administrative expense	$133	$199	$484	$624
Research and development expense	2	21	29	73
Total stock-based compensation expense	$135	$220	$513	$697

The following table summarizes the stock-based compensation expense that was recognized in the consolidated statements of operations for the years ended December 31,

(Dollars in thousands)	2022	2021
Selling, general and administrative	$784	$1,171
Research and development	78	143
Total	$862	$1,314

Weighted Average Assumptions used in Black-Scholes Option Pricing Model

The weighted-average assumptions used in the Black-Scholes option-pricing model are as follows for the stock options granted during the three and nine months ended September 30, 2023 and 2022:

	Three months ended September 30		Nine months ended September 30
	2023	2022	2023	2022
Expected volatility	131.06%	132.08%	152.59%	132.48%
Expected Life of options (years)	6.25	6.25	6.19	6.15
Expected dividend yield	0%	0%	0%	0%
Risk-free interest rate	4.29%	3.02%	4.16%	2.13%

The following table provides the weighted average assumptions used in the Black-Scholes option pricing model for the years ended December 31:

	2022	2021
Expected dividend yield	0%	0%
Risk-free interest rate	2.13%	1.19%
Expected volatility	132.48%	131.03%
Expected life (in years)	6.15	6.21

Income Taxes (FY) (Tables)

12 Months Ended

Dec. 31, 2022

Income Taxes [Abstract]

Domestic and Foreign Income (Loss) Before Income Taxes

Domestic and foreign income (loss) before income taxes consists of the following for the years ended December 31:

(in thousands)	2022	2021
Domestic	$(14,551)	$(19,582)
Foreign	35	37
Loss before income taxes	$(14,516)	$(19,545)

Components of Income Tax Expense

The components of income tax expense consist of the following for the years ended December 31:

(in thousands)	2022	2021
Current:
United States and state	$—	$—
Foreign, net	(9)	(9)
Deferred:
United States and state	—	—
Foreign	—	—
Total income tax expense	$(9)	$(9)

Actual Income Tax Expense Differs from Statutory Federal Income Tax Expense

Actual income tax expense differs from statutory federal income tax expense as follows for the years ended December 31:

(in thousands)	2022	2021
Statutory federal income tax benefit	$3,048	$4,109
State tax benefit, net of federal taxes	783	560
Foreign tax	(1)	(1)
Nondeductible/nontaxable items	548	(220)
Other	(41)	406
Valuation allowance (increase) decrease	(4,346)	(4,863)
Total income tax expense	$(9)	$(9)

Deferred Taxes

Deferred taxes consist of the following as of December 31:

(in thousands)	2022	2021
Deferred tax assets:
Noncurrent:
Accrued leave	$397	$59
Stock based compensation	360	368
Net operating loss carryforward	45,405	42,363
Other	42	131
Intangibles	1,786	723
R&D credit carryforward	531	531
Total deferred tax assets	48,521	44,175
Less: valuation allowance	(48,521)	(44,175)
Total	$—	$—

Fair Value of Financial Instruments, Roll-Forward of Fair Value of Level 3 Warrants (FY) (Details) - Warrant [Member] - USD ($) $ in Thousands		2 Months Ended
	Jan. 04, 2023	Dec. 31, 2022
Roll-Forward of Fair Value of Level 3 Warrants [Roll Forward]
Beginning balance	$ 6,868	$ 18,695
Change in fair value	755	(11,827)
Ending balance	$ 7,623	$ 6,868

Commitments and Contingencies (FY)	9 Months Ended	12 Months Ended
Commitments and Contingencies (FY)	Sep. 30, 2023	Dec. 31, 2022
Commitments and Contingencies [Abstract]
Commitments and Contingencies	Note 9 — Commitments and Contingencies Employee Retirement Plan: The Company has a 401(k) retirement plan that provides retirement benefits to substantially all full-time U.S. employees. Eligible employees may contribute a percentage of their annual compensation, subject to Internal Revenue Service limitations, with the Company matching a portion of the employees’ contributions at the discretion of the Company. Milestone Payment: On December 27, 2022, the Company entered into a license and distribution agreement with SeaStar Medical Holding Corporation, (Nasdaq: ICU), a medical device company developing proprietary solutions to reduce the consequences of dysregulated immune responses including hyperinflammation on vital organs (“SeaStar”), appointing the Company as the exclusive U.S. distributor to promote, advertise, market, distribute and sell certain products. As a part of this agreement, the Company agreed to pay SeaStar, a milestone payment of $450,000, upon its receipt of a Human Device Exemption (HDE) approval from the U.S. Food and Drug Administration’s (FDA). This payment is due within 30 days after achievement of the milestone event. As of September 30, 2023, SeaStar had not obtained such HDE approval, but the Company believes approval is reasonably possible. No liability for this milestone payment has been recorded in the financial statements as of September 30, 2023.	Note 10—Commitments and Contingencies Employee Retirement Plan The Company has a 401(k) plan that provides a retirement benefit to substantially all full-time U.S. employees. Eligible employees may contribute a percentage of their annual compensation, subject to Internal Revenue Service limitations, with the Company matching a portion of the employees’ contributions at the discretion of the Company. Matching contributions totaled $185,000 and $255,000 for the years ended December 31, 2022 and 2021, respectively. Non-refundable Technology License Fee On June 24, 2021, the Company entered into a research and development collaboration agreement with Koronis Biomedical Corporation (KBT) to design and develop an integrated continuous renal replacement therapy device. This agreement became effective on August 5, 2021, when KBT received approval of a $1.7 million grant from the National Institutes of Health (NIH) to support this project. As part of this agreement, the Company will pay KBT a non-refundable technology license fee of $428,160, payable in twelve equal monthly installments commencing on June 1, 2022. The Company has recorded a liability for the non-refundable technology license fee, with $178,400 included in Current Accounts Payable at December 31, 2022. The full amount of $428,160 was expensed and included in the Research and Development Expense line for the year ended December 31, 2021.

Fair Value of Financial Instruments, Roll-Forward of Fair Value of Level 3 Warrants (Q3) (Details) - Warrant [Member] - USD ($) $ in Thousands		2 Months Ended	9 Months Ended
	Jan. 04, 2023	Dec. 31, 2022	Sep. 30, 2023
Roll-Forward of Fair Value of Level 3 Warrants [Roll Forward]
Beginning balance	$ 6,868	$ 18,695	$ 7,623
Change in fair value	755	(11,827)
Warrants reclassified to equity			(7,623)
Ending balance	$ 7,623	$ 6,868	$ 0

Consolidated Balance Sheets (FY) (Parenthetical) - $ / shares	Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2021	Nov. 27, 2017
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	39,969,873	39,969,873	39,969,873
Preferred stock, shares outstanding (in shares)	0	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	100,000,000	100,000,000	100,000,000
Common stock, shares issued (in shares)	1,864,265	536,394	105,376
Common stock, shares outstanding (in shares)	1,864,265	536,394	105,376
Series A Junior Participating Preferred Stock [Member]
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	30,000	30,000	30,000
Preferred stock, shares outstanding (in shares)	0	0	0
Series F Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	127	127	127
Preferred stock, shares issued (in shares)	127	127	127	18,000
Preferred stock, shares outstanding (in shares)	127	127	127
Series I Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	1,049,280	1,049,280	0
Preferred stock, shares issued (in shares)	0	1,049,280	0
Preferred stock, shares outstanding (in shares)	0	1,049,280	0

Consolidated Statements of Operations and Comprehensive Loss (FY) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended		12 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Consolidated Statements of Operations and Comprehensive Loss [Abstract]
Net sales	$ 2,412			$ 2,065			$ 6,313	$ 6,204	$ 8,543	$ 7,921
Cost of goods sold	1,031			806			2,718	2,780	3,788	3,430
Gross profit	1,381			1,259			3,595	3,424	4,755	4,491
Operating expenses:
Selling, general and administrative	3,428			4,251			13,582	12,920	17,584	19,039
Research and development	1,117			928			4,050	3,141	4,342	4,978
Total operating expenses	4,545			5,179			17,632	16,061	21,926	24,017
Loss from operations	(3,164)			(3,920)			(14,037)	(12,637)	(17,171)	(19,526)
Other income (expense), net
Other income (expense), net	(204)			52			98	14	75	(19)
Financing expense									(9,247)	0
Change in fair value of warrant liability	0			0			(755)	0	11,827	0
Loss before income taxes	(3,368)			(3,868)			(14,694)	(12,623)	(14,516)	(19,545)
Income tax expense	(2)			(2)			(6)	(6)	(9)	(9)
Net loss	$ (3,370)	$ (4,845)	$ (6,485)	$ (3,870)	$ (4,286)	$ (4,473)	$ (14,700)	$ (12,629)	$ (14,525)	$ (19,554)
Basic loss per share (in dollars per share)	$ (1.81)			$ (36.72)			$ (10.21)	$ (119.85)	$ (83.55)	$ (285.36)
Diluted loss per share (in dollars per share)	$ (1.81)			$ (36.72)			$ (10.21)	$ (119.85)	$ (83.55)	$ (285.36)
Weighted average shares outstanding - basic (in shares)	1,864			105			1,439	105	174	69
Weighted average shares outstanding - diluted (in shares)	1,864			105			1,439	105	174	69
Other comprehensive loss:
Unrealized gain (loss) on marketable securities	$ 0	(61)	6						$ 80	$ (24)
Unrealized foreign currency translation adjustment	0	$ 0	$ (7)	$ 2	$ 1	$ (2)			(7)	(4)
Total comprehensive loss	$ (3,370)			$ (3,868)			$ (14,706)	$ (12,628)	$ (14,452)	$ (19,582)

Segment and Geographic Information (FY) (Details)	12 Months Ended
Segment and Geographic Information (FY) (Details)	Dec. 31, 2022 Segment
Segment and Geographic Information [Abstract]
Number of reportable segments	1

Property, Plant and Equipment (FY)

12 Months Ended

Dec. 31, 2022

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

Note 3—Property, Plant and Equipment

Property, plant and equipment were as follows:

(in thousands)	December 31, 2022	December 31, 2021
Production Equipment	$1,360	$1,321
Loaners and Demo Equipment	1,444	1,364
Computer Software and Equipment	719	714
Office Furniture & Fixtures	375	364
Leasehold Improvements	253	245
Total	4,151	4,008
Accumulated Depreciation	(3,171)	(2,820)
	$980	$1,188

Consolidated Balance Sheets (FY) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets
Cash and cash equivalents	$ 17,737	$ 8,742
Marketable securities	569	15,463
Accounts receivable	1,406	750
Inventories, net	2,661	2,843
Other current assets	396	328
Total current assets	22,769	28,126
Property, plant and equipment, net	980	1,188
Operating lease right-of-use asset	903	1,082
Other assets	21	21
TOTAL ASSETS	24,673	30,417
Current liabilities
Accounts payable and accrued liabilities	2,245	1,414
Accrued compensation	2,161	1,664
Current portion of operating lease liability	196	167
Current portion of finance lease liability	28	26
Other current liabilities	58	36
Total current liabilities	4,688	3,307
Common stock warrant liability	6,868	0
Operating lease liability	760	956
Finance lease liability	0	28
Other long-term liability	0	179
Total liabilities	12,316	4,470
Commitments and contingencies
Stockholders' equity
Preferred stock	0	0
Common stock as of December 31, 2022 and December 31, 2021, par value $0.0001 per share; authorized 100,000,000 shares, issued and outstanding 536,394 and 105,376, respectively	0	0
Additional paid-in capital	279,736	278,874
Accumulated other comprehensive income:
Foreign currency translation adjustment	(18)	(11)
Unrealized gain (loss) on marketable securities	56	(24)
Accumulated deficit	(267,417)	(252,892)
Total stockholders' equity	12,357	25,947
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	24,673	30,417
Series A Junior Participating Preferred Stock [Member]
Stockholders' equity
Preferred stock	0	0
Series F Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock	0	0
Series I Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock	$ 0	$ 0

Stock-Based Compensation (Q3)

9 Months Ended

12 Months Ended

Sep. 30, 2023

Dec. 31, 2022

Stock-Based Compensation

Note 4 — Stock-Based Compensation

Under the fair value recognition provisions of U.S. GAAP for accounting for stock-based compensation, the Company measures stock-based compensation expense at the grant date based on the fair value of the award and recognizes the compensation expense over the requisite service period, which is generally the vesting period.

The following table presents the classification of stock-based compensation expense recognized for the periods below:

	Three months ended September 30		Nine months ended September 30
(in thousands)	2023	2022	2023	2022
Selling, general and administrative expense	$133	$199	$484	$624
Research and development expense	2	21	29	73
Total stock-based compensation expense	$135	$220	$513	$697

During the three months ended September 30, 2023 and 2022, under the 2017 Equity Incentive Plan, the 2021 Inducement Plan, and the 2013 Non-Employee Directors’ Equity Incentive Plan, the Company granted 18,643 and 369 stock options, respectively, to its directors, officers and employees. During the nine months ended September 30, 2023 and 2022, the Company granted 125,410 and 5,577, respectively, to its directors, officers, employees and consultants. Vesting generally occurs over an immediate to 48-month period based on a time-of-service condition, although vesting acceleration is provided under one grant in the event that a certain milestone is met. The weighted-average grant date fair value of the stock-options issued during the three months ended September 30, 2023 and 2022 was $1.63 and $60.40 per share, respectively. The weighted-average grant date fair value of the stock options issued during the nine months ended September 30, 2023 and 2022 was $6.18 and $79.07 per share, respectively.

The total number of stock options outstanding as of September 30, 2023 and September 30, 2022 was 111,275 and 12,003, respectively.

The weighted-average assumptions used in the Black-Scholes option-pricing model are as follows for the stock options granted during the three and nine months ended September 30, 2023 and 2022:

	Three months ended September 30		Nine months ended September 30
	2023	2022	2023	2022
Expected volatility	131.06%	132.08%	152.59%	132.48%
Expected Life of options (years)	6.25	6.25	6.19	6.15
Expected dividend yield	0%	0%	0%	0%
Risk-free interest rate	4.29%	3.02%	4.16%	2.13%

During the three months ended September 30, 2023 and 2022, 2,576 and 823 stock options vested, respectively, and 21,372 and 343 stock options were expired or forfeited during these periods, respectively. During the nine months ended September 30, 2023 and 2022, 5,022 and 2,730 stock options vested, respectively, and 24,620 and 1,148 stock options were expired or forfeited during these periods, respectively. During the three and nine months ended September 30, 2023 and 2022, no options were exercised.

Note 5— Stock-Based Compensation

Stock Options and Restricted Stock Awards

The Company has various share-based compensation plans, including the Third Amended and Restated 2017 Equity Incentive Plan, the 2013 Non-Employee Directors’ Equity Incentive Plan and the 2021 Inducement Plan (collectively, the “Plans”). The Plans are designed to assist in attracting, motivating, and retaining employees and directors and to recognize the importance of employees to the long-term performance and success of the Company. The Company has also granted stock options to certain non-employees outside of the Plans.

The Company recognized stock-based compensation expense related to grants of stock options and common stock awards to employees, directors and consultants of $862,000 and $1.3 million during the years ended December 31, 2022 and 2021, respectively. The following table summarizes the stock-based compensation expense that was recognized in the consolidated statements of operations for the years ended December 31,

(Dollars in thousands)	2022	2021
Selling, general and administrative	$784	$1,171
Research and development	78	143
Total	$862	$1,314

The majority of the common stock awards and options to purchase common stock vest on the anniversary of the date of grant, which ranges from one to four years. Stock-based compensation expense related to these awards is recognized on a straight-line basis over the related vesting term in most cases, which generally is the service period. It is the Company’s policy to issue new shares upon the exercise of options.

Stock Options: The following is a summary of the Plans’ stock option activity during the years ended December 31:

	2022		2021
	Options Outstanding	Weighted Average Exercise Price	Options Outstanding	Weighted Average Exercise Price
Beginning Balance	7,481	$656.05	144	$40,534.00
Granted	5,833	83.96	9,081	444.83
Exercised	—	—	—	—
Forfeited/expired	(2,829)	410.34	(1,744)	2,332.06
Outstanding at December 31	10,485	$404.08	7,481	$656.05
Vested at December 31	3,531	$727.26	409	$4,218.40

For options outstanding and vested at December 31, 2022 and 2021, the weighted average remaining contractual life was 8.79 years and 8.63 years, respectively. There were no option exercises in 2022 or 2021. The total fair value of options that vested in 2022 and 2021 was $1.1 million, and $0.7 million, respectively, at the fair value of the options as of the date of grant.

Valuation Assumptions: The fair value of each stock option is estimated at the grant date using the Black-Scholes option pricing model. The fair value of stock options under the Black-Scholes option pricing model requires management to make assumptions regarding projected employee stock option exercise behaviors, risk-free interest rates, volatility of the Company’s stock price, and expected dividends.

The Company has not historically paid cash dividends to its stockholders and currently does not anticipate paying any cash dividends in the foreseeable future. As a result, the Company has assumed a dividend yield of

0%. The risk-free interest rate is based upon the rates of U.S. Treasury bills with a term that approximates the expected life of the option. Since the Company has limited historical exercise data to reasonably estimate the expected life of its option awards, the expected life is calculated using a simplified method. Expected volatility is based on historical volatility of the Company’s stock.

The following table provides the weighted average assumptions used in the Black-Scholes option pricing model for the years ended December 31:

	2022	2021
Expected dividend yield	0%	0%
Risk-free interest rate	2.13%	1.19%
Expected volatility	132.48%	131.03%
Expected life (in years)	6.15	6.21

The weighted-average fair value of stock options granted in 2022 and 2021 was $76.05 and $396.17, respectively. As of December 31, 2022, the total compensation cost related to all non-vested stock option awards not yet recognized was approximately $1.3 million and is expected to be recognized over the remaining weighted-average life of 2.54 years.

Warrants: Warrants to purchase 679,244 and 16,299 shares of common stock were outstanding on December 31, 2022 and 2021, respectively. As of December 31, 2022, warrants outstanding were exercisable at prices ranging from $25 to $189,000 per share and are exercisable over a period ranging from immediately to 5.8 years.

Stock-Based Compensation, Warrants (FY) (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2022	Jun. 30, 2023	Dec. 31, 2021
Class of Warrant or Right [Abstract]
Exercise price of warrants (in dollars per share)		$ 0
Warrants [Member]
Class of Warrant or Right [Abstract]
Warrants outstanding (in shares)	679,244		16,299
Warrants [Member] \| Minimum [Member]
Class of Warrant or Right [Abstract]
Exercise price of warrants (in dollars per share)	$ 25
Warrants [Member] \| Maximum [Member]
Class of Warrant or Right [Abstract]
Exercise price of warrants (in dollars per share)	$ 189,000
Warrants exercisable period	5 years 9 months 18 days

Condensed Consolidated Balance Sheets (Q3) (Parenthetical) - $ / shares	Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2021	Nov. 27, 2017
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	39,969,873	39,969,873	39,969,873
Preferred stock, shares outstanding (in shares)	0	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	100,000,000	100,000,000	100,000,000
Common stock, shares issued (in shares)	1,864,265	536,394	105,376
Common stock, shares outstanding (in shares)	1,864,265	536,394	105,376
Series A Junior Participating Preferred Stock [Member]
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	30,000	30,000	30,000
Preferred stock, shares outstanding (in shares)	0	0	0
Series F Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	127	127	127
Preferred stock, shares issued (in shares)	127	127	127	18,000
Preferred stock, shares outstanding (in shares)	127	127	127
Series I Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	1,049,280	1,049,280	0
Preferred stock, shares issued (in shares)	0	1,049,280	0
Preferred stock, shares outstanding (in shares)	0	1,049,280	0

Fair Value of Financial Instruments (Q3)

9 Months Ended

12 Months Ended

Sep. 30, 2023

Dec. 31, 2022

Fair Value of Financial Instruments

Note 5 — Fair Value of Financial Instruments

The Company’s financial instruments consist of cash and cash equivalents, marketable securities, and warrants.

•	Level 1 — Financial instruments with unadjusted quoted prices listed on active market exchanges.

•

•	Level 3 — Financial instruments that are not actively traded on a market exchange. This category includes situations where there is little, if any, market activity for the financial instrument. The prices are determined using significant unobservable inputs or valuation techniques.

All cash equivalents and marketable securities are considered Level 1 measurements for all periods presented.

The available-for-sale marketable securities primarily consist of investment-grade, U.S.-dollar-denominated fixed and floating rate debt, measured at fair value on a recurring basis.

Marketable securities

$569

The following is a roll-forward of the fair value of the Level 3 warrants:

(in thousands)
Balance at December 31, 2022			$6,868
Change in fair value			755
Balance at January 4, 2023 (revaluation date)			7,623
Warrants reclassified to equity			(7,623)
Balance at September 30, 2023			$—

Note 6—Fair Value of Financial Instruments

The Company’s financial instruments consist of cash and cash equivalents, marketable securities, and warrants.

•	Level 1 - Financial instruments with unadjusted quoted prices listed on active market exchanges.

•

•	Level 3 - Financial instruments that are not actively traded on a market exchange. This category includes situations where there is little, if any, market activity for the financial instrument. The prices are determined using significant unobservable inputs or valuation techniques.

All cash equivalents and marketable securities are considered Level 1 measurements for all periods presented.

The available-for-sale marketable securities primarily consist of investment-grade, U.S. dollar-denominated fixed and floating-rate debt, measured at fair value on a recurring basis.

	2022		2021
(Dollars in thousands)	Fair Value	Level 1	Fair Value	Level 1
Marketable securities	$569	$569	$15,463	$15,463

The following is a roll-forward of the fair value of Level 3 warrants:

(in thousands)
October 18, 2022 warrant issuance			$18,695
Change in fair value			(11,827)
Ending balance December 31, 2022			$6,868

Fair values were calculated using the following assumptions:

	Oct. 18, 2022	Dec. 31, 2022
Risk-free interest rates, adjusted for continuous compounding	4.16%	3.97%
Term (years)	6.18	6.11
Expected volatility	141.5%	145.3%
Dates and probability of future equity raises	various	various

Income Taxes (Q3)

9 Months Ended

12 Months Ended

Sep. 30, 2023

Dec. 31, 2022

Income Taxes [Abstract]

Income Taxes

Note 6 — Income Taxes

The Company provides for a valuation allowance when it is more likely than not that it will not realize a portion of its deferred tax assets. The Company has established a full valuation allowance for its U.S. and foreign deferred tax assets due to the uncertainty that enough taxable income will be generated in those taxing jurisdictions to utilize the assets. Therefore, the Company has not reflected any benefit of such deferred tax assets in the accompanying condensed consolidated financial statements.

As of September 30, 2023, there were no material changes to what the Company disclosed regarding tax uncertainties or penalties in its Annual Report on Form 10-K for the year ended December 31, 2022.

Note 7—Income Taxes

Domestic and foreign income (loss) before income taxes consists of the following for the years ended December 31:

(in thousands)	2022	2021
Domestic	$(14,551)	$(19,582)
Foreign	35	37
Loss before income taxes	$(14,516)	$(19,545)

The components of income tax expense consist of the following for the years ended December 31:

(in thousands)	2022	2021
Current:
United States and state	$—	$—
Foreign, net	(9)	(9)
Deferred:
United States and state	—	—
Foreign	—	—
Total income tax expense	$(9)	$(9)

Actual income tax expense differs from statutory federal income tax expense as follows for the years ended December 31:

(in thousands)	2022	2021
Statutory federal income tax benefit	$3,048	$4,109
State tax benefit, net of federal taxes	783	560
Foreign tax	(1)	(1)
Nondeductible/nontaxable items	548	(220)
Other	(41)	406
Valuation allowance (increase) decrease	(4,346)	(4,863)
Total income tax expense	$(9)	$(9)

Deferred taxes consist of the following as of December 31:

(in thousands)	2022	2021
Deferred tax assets:
Noncurrent:
Accrued leave	$397	$59
Stock based compensation	360	368
Net operating loss carryforward	45,405	42,363
Other	42	131
Intangibles	1,786	723
R&D credit carryforward	531	531
Total deferred tax assets	48,521	44,175
Less: valuation allowance	(48,521)	(44,175)
Total	$—	$—

As of December 31, 2022, the Company had federal net operating loss (“NOL”) carryforwards of approximately $198.1 million and state NOL carryforwards of $53.8 million. Approximately $120.1 million of federal NOL carryforwards will expire between 2024 and 2038. Pursuant to the Tax Cuts and Jobs Act of 2017, NOLs generated after 2017 of approximately $78.0 million do not expire. The expiration of state NOL carryforwards will vary by jurisdiction. In addition, future utilization of NOL carryforwards in the U.S. may be subject to certain limitations under Section 382 of the Internal Revenue Code. As of December 31, 2020, the Company no longer has tax loss carryforwards in the Commonwealth of Australia due to the dissolution of its Australian subsidiary in November 2020.

The Company provides for a valuation allowance when it is more likely than not that it will not realize a portion of the deferred tax assets. The Company has established a valuation allowance for U.S. and foreign deferred tax assets due to the uncertainty that enough taxable income will be generated in those taxing jurisdictions to utilize the assets. Therefore, the Company has not reflected any benefit of such deferred tax assets in the accompanying consolidated financial statements. For the years ended December 31, 2022, and 2021, the valuation allowance increased by $4.3 million and $4.9 million, respectively. The current year increase was primarily due to the federal and state net operating losses generated.

During 2022 and 2021, the Company believes it experienced an ownership change as defined in Section 382 of the Internal Revenue Code, which will limit the ability to utilize the Company’s net operating losses (NOLs). The Company may have experienced additional ownership changes in earlier years further limiting the NOL carryforwards that may be utilized. The Company has not yet completed a formal Section 382 analysis. The general limitation rules allow the Company to utilize its NOLs subject to an annual limitation that is determined by multiplying the federal long-term tax-exempt rate by the Company’s value immediately before the ownership change.

The accounting guidance related to uncertain tax positions prescribes a recognition threshold and measurement attribute for recognition and measurement of a tax position taken or expected to be taken in a tax return. It also provides guidance on de-recognition, classification, interest and penalties, accounting in interim periods, disclosure and transition. The Company had no material uncertain tax positions as of December 31, 2022 or 2021.

The Company recognizes interest and penalties on unrecognized tax benefits as well as interest received from favorable tax settlements within income tax expense. At December 31, 2022 and 2021, the Company recorded no accrued interest or penalties related to uncertain tax positions.

The tax years ended December 31, 2019 through December 31, 2022 remain open to examination by the Internal Revenue Service and by the various states where the Company is subject to taxation. Additionally, the returns of the Company’s Australian (through November 2020) and Irish subsidiaries are subject to examination by tax authorities of those jurisdictions for the tax years ended and subsequent to June 30, 2017 and December 31, 2017, respectively.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-14

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 270
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482526/740-270-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 17
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

Revision and Immaterial Correction of an Error in Previously Issued Financial Statements [Abstract]

Condensed Consolidated Statements of Stockholders' Equity (Q3) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid in Capital [Member]	Accumulated Other Comprehensive Income [Member]	Accumulated Deficit [Member]	Total
Balance at Dec. 31, 2020	$ 0	$ 249,663	$ (7)	$ (233,338)	$ 16,318
Balance (in shares) at Dec. 31, 2020	27,360
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(19,554)	(19,554)
Unrealized foreign currency translation adjustment	0	0	(4)	0	(4)
Unrealized gain on marketable securities	0	0	(24)	0	(24)
Stock-based compensation, net	$ 0	1,314	0	0	1,314
Stock-based compensation, net (in shares)	0
Issuance costs related to common stock offering	$ 0	(27,896)	0	0	(27,896)
Issuance of common stock from ATM offering (in shares)	78,014
Balance at Dec. 31, 2021	$ 0	278,874	(35)	(252,892)	25,947
Balance (in shares) at Dec. 31, 2021	105,376
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(4,473)	(4,473)
Unrealized foreign currency translation adjustment	0	0	(2)	0	(2)
Stock-based compensation, net	$ 0	241	0	0	241
Stock-based compensation, net (in shares)	0
Balance at Mar. 31, 2022	$ 0	279,115	(37)	(257,365)	21,713
Balance (in shares) at Mar. 31, 2022	105,376
Balance at Dec. 31, 2021	$ 0	278,874	(35)	(252,892)	25,947
Balance (in shares) at Dec. 31, 2021	105,376
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss					(12,629)
Balance at Sep. 30, 2022	$ 0	279,571	(34)	(265,521)	14,016
Balance (in shares) at Sep. 30, 2022	105,376
Balance at Dec. 31, 2021	$ 0	278,874	(35)	(252,892)	25,947
Balance (in shares) at Dec. 31, 2021	105,376
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(14,525)	(14,525)
Unrealized foreign currency translation adjustment	0	0	(7)	0	(7)
Unrealized gain on marketable securities	0	0	80	0	80
Stock-based compensation, net	$ 0	862	0	0	862
Stock-based compensation, net (in shares)	0
Issuance costs related to common stock offering	$ 0	0	0	0	0
Conversion of preferred stock into common stock	$ 0	0	0	0	0
Conversion of preferred stock into common stock (in shares)	221,078
Issuance of common stock from ATM offering (in shares)	209,940
Balance at Dec. 31, 2022	$ 0	279,736	38	(267,417)	12,357
Balance (in shares) at Dec. 31, 2022	536,394
Balance at Mar. 31, 2022	$ 0	279,115	(37)	(257,365)	21,713
Balance (in shares) at Mar. 31, 2022	105,376
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(4,286)	(4,286)
Unrealized foreign currency translation adjustment	0	0	1	0	1
Stock-based compensation, net	$ 0	236	0	0	236
Stock-based compensation, net (in shares)	0
Balance at Jun. 30, 2022	$ 0	279,351	(36)	(261,651)	17,664
Balance (in shares) at Jun. 30, 2022	105,376
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(3,870)	(3,870)
Unrealized foreign currency translation adjustment	0	0	2	0	2
Stock-based compensation, net	$ 0	220	0	0	220
Stock-based compensation, net (in shares)	0
Balance at Sep. 30, 2022	$ 0	279,571	(34)	(265,521)	14,016
Balance (in shares) at Sep. 30, 2022	105,376
Balance at Dec. 31, 2022	$ 0	279,736	38	(267,417)	12,357
Balance (in shares) at Dec. 31, 2022	536,394
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(6,485)	(6,485)
Unrealized foreign currency translation adjustment	0	0	(7)	0	(7)
Unrealized gain on marketable securities	0	0	6	0	6
Stock-based compensation, net	$ 0	181	0	0	181
Stock-based compensation, net (in shares)	0
Issuance costs related to common stock offering	$ 0	(11)	0	0	(11)
Conversion of preferred stock into common stock	$ 0	0	0	0	0
Conversion of preferred stock into common stock (in shares)	10,493
Reclassification of warrants to equity	$ 0	7,623	0	0	7,623
Conversion of warrants into common stock	$ 0	0	0	0	0
Conversion of warrants into common stock (in shares)	660,045
Balance at Mar. 31, 2023	$ 0	287,529	37	(273,902)	13,664
Balance (in shares) at Mar. 31, 2023	1,206,932
Balance at Dec. 31, 2022	$ 0	279,736	38	(267,417)	12,357
Balance (in shares) at Dec. 31, 2022	536,394
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss					(14,700)
Balance at Sep. 30, 2023	$ 0	289,980	(24)	(282,117)	7,839
Balance (in shares) at Sep. 30, 2023	1,864,265
Balance at Mar. 31, 2023	$ 0	287,529	37	(273,902)	13,664
Balance (in shares) at Mar. 31, 2023	1,206,932
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(4,845)	(4,845)
Unrealized foreign currency translation adjustment	0	0	0	0	0
Unrealized gain on marketable securities	0	0	(61)	0	(61)
Stock-based compensation, net	$ 0	197	0	0	197
Stock-based compensation, net (in shares)	0
Issuance costs related to common stock offering	$ 0	(98)	0	0	(98)
Issuance of common stock from ATM offering	$ 0	2,217	0	0	2,217
Issuance of common stock from ATM offering (in shares)	657,333
Balance at Jun. 30, 2023	$ 0	289,845	(24)	(278,747)	11,074
Balance (in shares) at Jun. 30, 2023	1,864,265
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(3,370)	(3,370)
Unrealized foreign currency translation adjustment	0	0	0	0	0
Unrealized gain on marketable securities	0	0	0	0	0
Stock-based compensation, net	$ 0	135	0	0	135
Stock-based compensation, net (in shares)	0
Issuance costs related to common stock offering	$ 0	0	0	0	0
Issuance of common stock from ATM offering	$ 0	0	0	0	0
Issuance of common stock from ATM offering (in shares)	0
Balance at Sep. 30, 2023	$ 0	$ 289,980	$ (24)	$ (282,117)	$ 7,839
Balance (in shares) at Sep. 30, 2023	1,864,265

Fair Value of Financial Instruments, Fair Values Assumptions (FY) (Details)		12 Months Ended
	Oct. 18, 2022	Dec. 31, 2022
Valuation Technique and Input, Description [Abstract]
Dates and probability of future equity raises	various	various
Risk-Free Interest Rate, Adjusted for Continuous Compounding [Member]
Valuation Technique and Input, Description [Abstract]
Measurement input	0.0416	0.0397
Term [Member]
Valuation Technique and Input, Description [Abstract]
Term	6 years 2 months 4 days	6 years 1 month 9 days
Expected Volatility [Member]
Valuation Technique and Input, Description [Abstract]
Measurement input	1.415	1.453

Commitments and Contingencies (Q3)	9 Months Ended	12 Months Ended
Commitments and Contingencies (Q3)	Sep. 30, 2023	Dec. 31, 2022
Commitments and Contingencies [Abstract]
Commitments and Contingencies	Note 9 — Commitments and Contingencies Employee Retirement Plan: The Company has a 401(k) retirement plan that provides retirement benefits to substantially all full-time U.S. employees. Eligible employees may contribute a percentage of their annual compensation, subject to Internal Revenue Service limitations, with the Company matching a portion of the employees’ contributions at the discretion of the Company. Milestone Payment: On December 27, 2022, the Company entered into a license and distribution agreement with SeaStar Medical Holding Corporation, (Nasdaq: ICU), a medical device company developing proprietary solutions to reduce the consequences of dysregulated immune responses including hyperinflammation on vital organs (“SeaStar”), appointing the Company as the exclusive U.S. distributor to promote, advertise, market, distribute and sell certain products. As a part of this agreement, the Company agreed to pay SeaStar, a milestone payment of $450,000, upon its receipt of a Human Device Exemption (HDE) approval from the U.S. Food and Drug Administration’s (FDA). This payment is due within 30 days after achievement of the milestone event. As of September 30, 2023, SeaStar had not obtained such HDE approval, but the Company believes approval is reasonably possible. No liability for this milestone payment has been recorded in the financial statements as of September 30, 2023.	Note 10—Commitments and Contingencies Employee Retirement Plan The Company has a 401(k) plan that provides a retirement benefit to substantially all full-time U.S. employees. Eligible employees may contribute a percentage of their annual compensation, subject to Internal Revenue Service limitations, with the Company matching a portion of the employees’ contributions at the discretion of the Company. Matching contributions totaled $185,000 and $255,000 for the years ended December 31, 2022 and 2021, respectively. Non-refundable Technology License Fee On June 24, 2021, the Company entered into a research and development collaboration agreement with Koronis Biomedical Corporation (KBT) to design and develop an integrated continuous renal replacement therapy device. This agreement became effective on August 5, 2021, when KBT received approval of a $1.7 million grant from the National Institutes of Health (NIH) to support this project. As part of this agreement, the Company will pay KBT a non-refundable technology license fee of $428,160, payable in twelve equal monthly installments commencing on June 1, 2022. The Company has recorded a liability for the non-refundable technology license fee, with $178,400 included in Current Accounts Payable at December 31, 2022. The full amount of $428,160 was expensed and included in the Research and Development Expense line for the year ended December 31, 2021.

Revision and Immaterial Correction of an Error in Previously Issued Financial Statements (FY)

12 Months Ended

Dec. 31, 2022

Revision and Immaterial Correction of an Error in Previously Issued Financial Statements

Note 13—Revision and Immaterial Correction of an Error in Previously Issued Financial Statements

The Company identified an error related to the classification and disclosures of marketable securities in our consolidated financial statements as of and for the year ended December 31, 2021 as reported on Form 10-K. In our December 31, 2021 consolidated financial statements, we incorrectly classified short term marketable securities as a cash and cash equivalents on the consolidated balance sheet. There was no change to the total current assets on the consolidated balance sheet. Additionally, we recorded an unrealized gain in other income on the consolidated statement of operations. This unrealized gain should have been recorded as accumulated other comprehensive income in the consolidated statement of operations and comprehensive loss and the consolidated statements of stockholders’ equity. This correction also impacts the consolidated statement of cash flows, as the purchase of these securities and redemption of these securities would be shown in the investing activities section. In accordance with ASC 250, Accounting Changes and Error Corrections, we evaluated the materiality of the errors from quantitative and qualitative perspectives and concluded that the errors were immaterial to the Company’s 2021 audited financial statements. Since these revisions were not material to any prior period financial statements, no amendments to previously filed financial statements are required. Consequently, the Company has corrected these immaterial errors by revising the December 31, 2021 consolidated financial statements presented herein.

The tables below present the effect of the financial statement adjustments related to the revision discussed above of the Company’s previously reported financial statements as of and for the periods ended December 31, 2021.

The effect of the immaterial correction of an error on our previously filed audited consolidated financial statements as of December 31, 2021 and for the year then ended is as follows:

(in thousands)	December 31, 2021
Consolidated Balance Sheet	As reported	Adjustment	As revised
Cash and cash equivalents	$24,205	$(15,463)	$8,742
Marketable securities	—	15,463	15,463
Total Current Assets	28,126	—	28,126

Consolidated Statement of Operations and Comprehensive Loss

(in thousands)	As reported	Adjustment	As revised
Other income (expense)	(43)	24	(19)
Unrealized gains (losses) on marketable securities	—	(24)	(24)
	(43)	—	(43)

Consolidated Statement of Cash Flows

(in thousands)	As reported	Adjustment	As revised
Net realized and unrealized gains on marketable securities	—	13	13
Net cash provided in operations	—	13	13
Purchases of marketable securities	—	(18,850)	(18,850)
Proceeds from sales of marketable securities	—	3,350	3,350
Net cash used in investing activities	—	(15,500)	(15,500)
Beginning cash and cash equivalents	14,437	—	14,437
Ending cash and cash equivalents	$24,205	$(15,463)	$8,742

Operating Leases (FY) (Tables)

12 Months Ended

Dec. 31, 2022

Operating Leases [Abstract]

Cost Components of Operating Leases

The cost components of the Company’s operating lease were as follows for the year ended December 31:

(in thousands)	2022	2021
Operating lease cost	$238	$219
Variable lease cost	127	123
Total	$365	$342

Maturities of Lease Liability

Maturities of our lease liability for the Company’s operating lease are as follows as of December 31:

(in thousands)			2022
2023			$249
2024			257
2025			264
2026			272
2027			69
Total lease payments			1,111
Less: Interest			(155)
Present value of lease liability			$956

Commitments and Contingencies (FY) (Details)		12 Months Ended
Commitments and Contingencies (FY) (Details)	Aug. 05, 2021 USD ($) Installment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Employee Retirement Plan [Abstract]
Employer's matching contribution		$ 185,000	$ 255,000
Koronis Biomedical Corporation [Member]
Commitments and Contingencies [Abstract]
Amount of grant approval received	$ 1,700,000
Non-refundable technology license fee	$ 428,160
Number of equal monthly installments \| Installment	12
Research and Development Expense [Member] \| Koronis Biomedical Corporation [Member]
Commitments and Contingencies [Abstract]
Non-refundable technology license fee expenses			$ 428,160
Accounts Payable [Member] \| Koronis Biomedical Corporation [Member]
Commitments and Contingencies [Abstract]
Non-refundable technology license fee		$ 178,400

Stock-Based Compensation (FY) (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2023

Dec. 31, 2022

Summary of Stock-Based Compensation Expense

The following table presents the classification of stock-based compensation expense recognized for the periods below:

	Three months ended September 30		Nine months ended September 30
(in thousands)	2023	2022	2023	2022
Selling, general and administrative expense	$133	$199	$484	$624
Research and development expense	2	21	29	73
Total stock-based compensation expense	$135	$220	$513	$697

The following table summarizes the stock-based compensation expense that was recognized in the consolidated statements of operations for the years ended December 31,

(Dollars in thousands)	2022	2021
Selling, general and administrative	$784	$1,171
Research and development	78	143
Total	$862	$1,314

Summary of Plan Stock Option Activity

The following is a summary of the Plans’ stock option activity during the years ended December 31:

	2022		2021
	Options Outstanding	Weighted Average Exercise Price	Options Outstanding	Weighted Average Exercise Price
Beginning Balance	7,481	$656.05	144	$40,534.00
Granted	5,833	83.96	9,081	444.83
Exercised	—	—	—	—
Forfeited/expired	(2,829)	410.34	(1,744)	2,332.06
Outstanding at December 31	10,485	$404.08	7,481	$656.05
Vested at December 31	3,531	$727.26	409	$4,218.40

Weighted Average Assumptions used in Black-Scholes Option Pricing Model

The weighted-average assumptions used in the Black-Scholes option-pricing model are as follows for the stock options granted during the three and nine months ended September 30, 2023 and 2022:

	Three months ended September 30		Nine months ended September 30
	2023	2022	2023	2022
Expected volatility	131.06%	132.08%	152.59%	132.48%
Expected Life of options (years)	6.25	6.25	6.19	6.15
Expected dividend yield	0%	0%	0%	0%
Risk-free interest rate	4.29%	3.02%	4.16%	2.13%

The following table provides the weighted average assumptions used in the Black-Scholes option pricing model for the years ended December 31:

	2022	2021
Expected dividend yield	0%	0%
Risk-free interest rate	2.13%	1.19%
Expected volatility	132.48%	131.03%
Expected life (in years)	6.15	6.21

Revenue Recognition (FY)	9 Months Ended	12 Months Ended
Revenue Recognition (FY)	Sep. 30, 2023	Dec. 31, 2022
Revenue Recognition [Abstract]
Revenue Recognition	Note 2 — Revenue Recognition Net Sales: The Company sells its products in the United States primarily through a direct salesforce. Customers who purchase the Company’s products include hospitals and clinics throughout the United States. In countries outside the United States, the Company sells its products through a limited number of specialty healthcare distributors in Austria, Brazil, Colombia, The Czech Republic, Germany, Greece, Hong Kong, India, Indonesia, Israel, Italy, Panama, Romania, Singapore, Slovakia, Spain, Switzerland, Thailand, United Arab Emirates, and the United Kingdom. These distributors resell the Company’s products to hospitals and clinics in their respective geographies. International revenue represents 5% of net sales for the three and nine months ended September 30, 2023 and 2022. Revenue from product sales is recognized when the customer or distributor obtains control of the product, which occurs at a point in time, most frequently upon shipment of the product or receipt of the product, depending on shipment terms. The Company’s standard shipping terms are FOB shipping point unless the customer requests that control and title to the inventory transfer upon delivery. Revenue is measured as the amount of consideration we expect to receive, adjusted for any applicable estimates of variable consideration and other factors affecting the transaction price, which is based on the invoiced price, in exchange for transferring products. All revenue is recognized when the Company satisfies its performance obligations under the contract. The majority of the Company’s contracts have a single performance obligation and are short term in nature. The Company has entered into extended service plans with customers whose related revenue is recognized over time. This revenue represents less than 1% of net sales for the three and nine months ended September 30, 2023 and 2022. The unfulfilled performance obligations related to these extended service plans are included in deferred revenue, which is included in other current liabilities on the consolidated balance sheets. The majority of the deferred revenue is expected to be recognized within one year. Sales taxes and value added taxes in foreign jurisdictions that are collected from customers and remitted to governmental authorities are accounted for on a net basis and therefore are excluded from net sales. Revenue includes shipment and handling fees charged to customers. Shipping and handling costs associated with outbound freight after control over a product has transferred to a customer are accounted for as a fulfillment cost and are included in cost of goods sold. Product Returns: The Company offers customers a limited right of return for its products in case of non-conformity or performance issues. The Company estimates the amount of its product sales that may be returned by its customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized. The Company currently estimates product return liabilities using available industry data and its own historical sales and returns information. The Company has not received any returns to date and believes that future returns of its products will be minimal. Therefore, revenue recognized is not currently impacted by variable consideration related to product returns.	Note 2 – Revenue Recognition Net Sales The Company sells its products in the United States primarily through a direct salesforce. Customers who purchase the Company’s products include hospitals and clinics throughout the United States. In countries outside the United States, the Company sells its products through a limited number of specialty healthcare distributors in Austria, Brazil, Colombia, the Czech Republic, Germany, Greece, Hong Kong, India, Israel, Italy, Panama. Romania, Singapore, Slovakia, Spain, Switzerland, Thailand, United Arab Emirates, and the United Kingdom. These distributors resell the Company’s products to hospitals and clinics in their respective geographies. Revenue from product sales is recognized when the customer or distributor obtains control of the product, which occurs at a point in time, most frequently upon shipment of the product or receipt of the product, depending on shipment terms. The Company’s standard shipping terms are FOB shipping point unless the customer requests that control and title to the inventory transfer upon delivery. Revenue is measured as the amount of consideration we expect to receive, adjusted for any applicable estimates of variable consideration and other factors affecting the transaction price, which is based on the invoiced price, in exchange for transferring products. All revenue is recognized when the Company satisfies its performance obligations under the contract. The majority of the Company’s contracts have a single performance obligation and are short term in nature. The Company has entered into extended service plans with customers, which are recognized over time. This revenue represents less than 1% of net sales for each of the years ended December 31, 2022 and 2021. The unfulfilled performance obligations related to these extended service plans are included in deferred revenue, which is included in other current liabilities on the consolidated balance sheets. The majority of the deferred revenue is expected to be recognized within one year. Sales taxes and value added taxes in foreign jurisdictions that are collected from customers and remitted to governmental authorities are accounted for on a net basis and therefore are excluded from net sales. Revenue includes shipment and handling fees charged to customers. Shipping and handling costs associated with outbound freight after control over a product has transferred to a customer are accounted for as a fulfillment cost and are included in cost of goods sold. Product Returns: The Company offers customers a limited right of return for its product in case of non-conformity or performance issues. The Company estimates the amount of its product sales that may be returned by its customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized. The Company currently estimates product return liabilities using available industry data and its own historical sales and returns information. The Company has not received any returns to date and believes that future returns of its products will be minimal. Therefore, revenue recognized is not currently impacted by variable consideration related to product returns.

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-9

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-10

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-15

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-13

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Topic 606
-Publisher FASB
-URI https://asc.fasb.org//606/tableOfContent

Revision and Immaterial Correction of an Error in Previously Issued Financial Statements [Abstract]

Revision and Immaterial Correction of an Error in Previously Issued Financial Statements (FY) (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Consolidated Balance Sheet [Abstract]
Cash and cash equivalents	$ 4,930				$ 4,930		$ 17,737	$ 8,742
Marketable securities	0				0		569	15,463
Total current assets	9,638				9,638		22,769	28,126
Consolidated Statement of Operations and Comprehensive Loss [Abstract]
Other income (expense)	(204)			$ 52	98	$ 14	75	(19)
Unrealized gains (losses) on marketable securities	0	$ (61)	$ 6				80	(24)
Total comprehensive loss								(43)
Consolidated Statement of Cash Flows [Abstract]
Net realized and unrealized gains on marketable securities							124	13
Net cash used in operating activities								13
Purchases of marketable securities							0	(18,850)
Proceeds from sale of marketable securities					578	0	14,850	3,350
Net cash provided (used) in investing activities								(15,500)
Cash and cash equivalents - beginning of period			$ 17,737		17,737	8,742	8,742	14,437
Cash and cash equivalents - end of period	$ 4,930			$ 12,053	$ 4,930	12,053	17,737	8,742
As Reported [Member]
Consolidated Balance Sheet [Abstract]
Cash and cash equivalents								24,205
Marketable securities								0
Total current assets								28,126
Consolidated Statement of Operations and Comprehensive Loss [Abstract]
Other income (expense)								(43)
Unrealized gains (losses) on marketable securities								0
Total comprehensive loss								(43)
Consolidated Statement of Cash Flows [Abstract]
Net realized and unrealized gains on marketable securities								0
Net cash used in operating activities								0
Purchases of marketable securities								0
Proceeds from sale of marketable securities								0
Net cash provided (used) in investing activities								0
Cash and cash equivalents - beginning of period						24,205	24,205	14,437
Cash and cash equivalents - end of period								24,205
Adjustment [Member]
Consolidated Balance Sheet [Abstract]
Cash and cash equivalents								(15,463)
Marketable securities								15,463
Total current assets								0
Consolidated Statement of Operations and Comprehensive Loss [Abstract]
Other income (expense)								24
Unrealized gains (losses) on marketable securities								(24)
Total comprehensive loss								0
Consolidated Statement of Cash Flows [Abstract]
Net realized and unrealized gains on marketable securities								13
Net cash used in operating activities								13
Purchases of marketable securities								(18,850)
Proceeds from sale of marketable securities								3,350
Net cash provided (used) in investing activities								(15,500)
Cash and cash equivalents - beginning of period						$ (15,463)	$ (15,463)	0
Cash and cash equivalents - end of period								$ (15,463)

Revision and Immaterial Correction of an Error in Previously Issued Financial Statements (FY) (Tables)

12 Months Ended

Dec. 31, 2022

Immaterial Correction of Error on Consolidated Financial Statements

The effect of the immaterial correction of an error on our previously filed audited consolidated financial statements as of December 31, 2021 and for the year then ended is as follows:

(in thousands)	December 31, 2021
Consolidated Balance Sheet	As reported	Adjustment	As revised
Cash and cash equivalents	$24,205	$(15,463)	$8,742
Marketable securities	—	15,463	15,463
Total Current Assets	28,126	—	28,126

Consolidated Statement of Operations and Comprehensive Loss

(in thousands)	As reported	Adjustment	As revised
Other income (expense)	(43)	24	(19)
Unrealized gains (losses) on marketable securities	—	(24)	(24)
	(43)	—	(43)

Consolidated Statement of Cash Flows

(in thousands)	As reported	Adjustment	As revised
Net realized and unrealized gains on marketable securities	—	13	13
Net cash provided in operations	—	13	13
Purchases of marketable securities	—	(18,850)	(18,850)
Proceeds from sales of marketable securities	—	3,350	3,350
Net cash used in investing activities	—	(15,500)	(15,500)
Beginning cash and cash equivalents	14,437	—	14,437
Ending cash and cash equivalents	$24,205	$(15,463)	$8,742

Income Taxes, Domestic and Foreign Income (Loss) Before Income Taxes (FY) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Domestic and foreign income (loss) before income taxes [Abstract]
Domestic					$ (14,551)	$ (19,582)
Foreign					35	37
Loss before income taxes	$ (3,368)	$ (3,868)	$ (14,694)	$ (12,623)	$ (14,516)	$ (19,545)

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(11))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-31

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 235
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-05(b)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479557/942-235-S99-1

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 25
-Paragraph 1
-SubTopic 20
-Topic 940
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481913/940-20-25-1

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(10))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(15))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

Nature of Business and Significant Accounting Policies, Property, Plant and Equipment and Revenue Recognition (FY) (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023 Customer	Sep. 30, 2022 Customer	Sep. 30, 2023 Customer	Sep. 30, 2022 Customer	Dec. 31, 2022 USD ($) Customer	Dec. 31, 2021 USD ($) Customer
Property, Plant and Equipment [Abstract]
Depreciation expense					$ 372,000	$ 488,000
Impairment losses recognized					$ 0	$ 0
Production Equipment [Member] \| Minimum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives					3 years
Production Equipment [Member] \| Maximum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives					7 years
Office Furniture and Fixtures [Member] \| Minimum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives					3 years
Office Furniture and Fixtures [Member] \| Maximum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives					5 years
Computer Software and Equipment [Member] \| Minimum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives					3 years
Computer Software and Equipment [Member] \| Maximum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives					4 years
Loaners and Demo Equipment [Member] \| Minimum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives					1 year
Loaners and Demo Equipment [Member] \| Maximum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives					5 years
Leasehold Improvements [Member] \| Minimum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives					3 years
Leasehold Improvements [Member] \| Maximum [Member]
Property, Plant and Equipment [Abstract]
Estimated useful lives					5 years
ASC 606 [Member] \| Net Sales [Member]
Revenue Recognition [Abstract]
Number of major customers \| Customer	2	1	2	2	1	2
ASC 606 [Member] \| Customer One [Member] \| Net Sales [Member] \| Customer Concentration Risk [Member]
Revenue Recognition [Abstract]
Concentration risk percentage	21.00%	12.00%	17.00%	13.00%	12.50%	12.30%
ASC 606 [Member] \| Customer Two [Member] \| Net Sales [Member] \| Customer Concentration Risk [Member]
Revenue Recognition [Abstract]
Concentration risk percentage	11.00%		12.00%	10.00%		10.70%

Condensed Consolidated Statements of Operations and Comprehensive Loss (Q3) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Consolidated Statements of Operations and Comprehensive Loss [Abstract]
Net sales	$ 2,412	$ 2,065	$ 6,313	$ 6,204
Cost of goods sold	1,031	806	2,718	2,780
Gross profit	1,381	1,259	3,595	3,424
Operating expenses:
Selling, general and administrative	3,428	4,251	13,582	12,920
Research and development	1,117	928	4,050	3,141
Total operating expenses	4,545	5,179	17,632	16,061
Loss from operations	(3,164)	(3,920)	(14,037)	(12,637)
Other income (expense), net	(204)	52	98	14
Change in fair value of warrant liability	0	0	(755)	0
Loss before income taxes	(3,368)	(3,868)	(14,694)	(12,623)
Income tax expense	(2)	(2)	(6)	(6)
Net loss	$ (3,370)	$ (3,870)	$ (14,700)	$ (12,629)
Basic loss per share (in dollars per share)	$ (1.81)	$ (36.72)	$ (10.21)	$ (119.85)
Diluted loss per share (in dollars per share)	$ (1.81)	$ (36.72)	$ (10.21)	$ (119.85)
Weighted average shares outstanding - basic (in shares)	1,864	105	1,439	105
Weighted average shares outstanding - diluted (in shares)	1,864	105	1,439	105
Other comprehensive loss:
Foreign currency translation adjustments	$ 0	$ 2	$ (6)	$ 1
Total comprehensive loss	$ (3,370)	$ (3,868)	$ (14,706)	$ (12,628)

Fair Value of Financial Instruments (Q3) (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2023

Dec. 31, 2022

Available-for-Sale Marketable Securities Measured at Fair Value on Recurring Basis

The available-for-sale marketable securities primarily consist of investment-grade, U.S.-dollar-denominated fixed and floating rate debt, measured at fair value on a recurring basis.

Marketable securities

$569

The available-for-sale marketable securities primarily consist of investment-grade, U.S. dollar-denominated fixed and floating-rate debt, measured at fair value on a recurring basis.

	2022		2021
(Dollars in thousands)	Fair Value	Level 1	Fair Value	Level 1
Marketable securities	$569	$569	$15,463	$15,463

Roll-Forward of Fair Value of Level 3 Warrants

The following is a roll-forward of the fair value of the Level 3 warrants:

(in thousands)
Balance at December 31, 2022			$6,868
Change in fair value			755
Balance at January 4, 2023 (revaluation date)			7,623
Warrants reclassified to equity			(7,623)
Balance at September 30, 2023			$—

The following is a roll-forward of the fair value of Level 3 warrants:

(in thousands)
October 18, 2022 warrant issuance			$18,695
Change in fair value			(11,827)
Ending balance December 31, 2022			$6,868

Fair Value of Financial Instruments, Available-for-Sale Marketable Securities Measured at Fair Value on Recurring Basis (Q3) (Details) - Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2021
Available-for-sale marketable securities [Abstract]
Marketable securities	$ 0	$ 569	$ 15,463
Level 1 [Member]
Available-for-sale marketable securities [Abstract]
Marketable securities	$ 0	$ 569	$ 15,463

Nature of Business and Basis of Presentation, Loss Per Share (Q3) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Potential shares of common stock that are not included in the calculation of diluted net loss per share [Abstract]
Potential shares of common stock that are not included in the calculation of diluted net loss per share (in shares)			1,424,626	29,388	705,302	74,580
Reported net loss with reported net loss per share [Abstract]
Net loss	$ (3,370)	$ (3,870)	$ (14,700)	$ (12,629)	$ (14,525)	$ (19,545)
Weighted average shares outstanding - basic (in shares)	1,864,000	105,000	1,439,000	105,000	174,000	69,000
Weighted average shares outstanding - diluted (in shares)	1,864,000	105,000	1,439,000	105,000	174,000	69,000
Basic loss per share (in dollars per share)	$ (1.81)	$ (36.72)	$ (10.21)	$ (119.85)	$ (83.55)	$ (285.36)
Diluted loss per share (in dollars per share)	$ (1.81)	$ (36.72)	$ (10.21)	$ (119.85)	$ (83.55)	$ (285.36)
Stock Options [Member]
Potential shares of common stock that are not included in the calculation of diluted net loss per share [Abstract]
Potential shares of common stock that are not included in the calculation of diluted net loss per share (in shares)			111,275	11,910	10,485	7,481
Warrants to Purchase Common Stock [Member]
Potential shares of common stock that are not included in the calculation of diluted net loss per share [Abstract]
Potential shares of common stock that are not included in the calculation of diluted net loss per share (in shares)			1,308,271	16,970	679,244	16,299
Series F Convertible Preferred Stock [Member]
Potential shares of common stock that are not included in the calculation of diluted net loss per share [Abstract]
Potential shares of common stock that are not included in the calculation of diluted net loss per share (in shares)			5,080	508	5,080	50,800

Stock-Based Compensation, Stock Options (FY) (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Stock-Based Compensation Expense Items [Abstract]
Stock-based compensation expense	$ 135,000	$ 220,000	$ 513,000	$ 697,000	$ 862,000	$ 1,314,000
Minimum [Member]
Additional Disclosures [Abstract]
Award vesting period					1 year
Maximum [Member]
Additional Disclosures [Abstract]
Award vesting period					4 years
Selling, General and Administrative [Member]
Stock-Based Compensation Expense Items [Abstract]
Stock-based compensation expense	133,000	199,000	484,000	624,000	$ 784,000	1,171,000
Research and Development [Member]
Stock-Based Compensation Expense Items [Abstract]
Stock-based compensation expense	$ 2,000	$ 21,000	$ 29,000	$ 73,000	$ 78,000	$ 143,000
Stock Options [Member]
Stock Options Activity [Roll Forward]
Outstanding, beginning balance (in shares)			10,485	7,481	7,481	144
Granted (in shares)	18,643	369	125,410	5,577	5,833	9,081
Exercised (in shares)	0	0	0	0	0	0
Forfeited/expired (in shares)	(21,372)	(343)	(24,620)	(1,148)	(2,829)	(1,744)
Outstanding, ending balance (in shares)	111,275	12,003	111,275	12,003	10,485	7,481
Vested at the end of the year (in shares)					3,531	409
Weighted Average Exercise Price [Abstract]
Outstanding, beginning balance (in dollars per share)			$ 404.08	$ 656.05	$ 656.05	$ 40,534
Granted (in dollars per share)					83.96	444.83
Exercised (in dollars per share)					0	0
Forfeited/expired (in dollars per share)					410.34	2,332.06
Outstanding, ending balance (in dollars per share)					404.08	656.05
Vested at the end of the year (in dollars per share)					$ 727.26	$ 4,218.4
Weighted Average Remaining Contractual Term [Abstract]
Options outstanding, weighted average remaining contractual life					8 years 9 months 14 days	8 years 9 months 14 days
Options vested, weighted average remaining contractual life					8 years 7 months 17 days	8 years 7 months 17 days
Aggregate Intrinsic Value [Abstract]
Fair value of options, vested					$ 1,100,000	$ 700,000
Weighted Average Assumptions used in Black-Scholes Option Pricing Model [Abstract]
Expected dividend yield	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%
Risk-free interest rate	4.29%	3.02%	4.16%	2.13%	2.13%	1.19%
Expected volatility	131.06%	132.08%	152.59%	132.48%	132.48%	131.03%
Expected life	6 years 3 months	6 years 3 months	6 years 2 months 8 days	6 years 1 month 24 days	6 years 1 month 24 days	6 years 2 months 15 days
Additional Disclosures [Abstract]
Award vesting period			48 months
Weighted-average fair value of options granted (in dollars per share)	$ 1.63	$ 60.4	$ 6.18	$ 79.07	$ 76.05	$ 396.17
Total unrecognized compensation costs related to non-vested stock option awards					$ 1,300,000
Unrecognized compensation costs related to non-vested stock option awards, recognition life					2 years 6 months 14 days

Stock-Based Compensation (Q3) (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
Stock-Based Compensation (Q3) (Details) - USD ($)	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Stock-Based Compensation Expense Items [Abstract]
Stock-based compensation expense	$ 135,000	$ 220,000	$ 513,000	$ 697,000	$ 862,000	$ 1,314,000
Selling, General and Administrative Expense [Member]
Stock-Based Compensation Expense Items [Abstract]
Stock-based compensation expense	133,000	199,000	484,000	624,000	784,000	1,171,000
Research and Development Expense [Member]
Stock-Based Compensation Expense Items [Abstract]
Stock-based compensation expense	$ 2,000	$ 21,000	$ 29,000	$ 73,000	$ 78,000	$ 143,000
Stock Options [Member]
Additional Disclosures [Abstract]
Stock options granted (in shares)	18,643	369	125,410	5,577	5,833	9,081
Vesting period			48 months
Weighted average grant date fair value of stock options issued (in dollars per share)	$ 1.63	$ 60.4	$ 6.18	$ 79.07	$ 76.05	$ 396.17
Outstanding stock options (in shares)	111,275	12,003	111,275	12,003	10,485	7,481	144
Stock options vested (in shares)	2,576	823	5,022	2,730
Stock options expired or forfeited (in shares)	21,372	343	24,620	1,148	2,829	1,744
Exercise of stock options (in shares)	0	0	0	0	0	0
Weighted Average Assumptions used in Black-Scholes Option Pricing Model [Abstract]
Expected volatility	131.06%	132.08%	152.59%	132.48%	132.48%	131.03%
Expected Life of options (years)	6 years 3 months	6 years 3 months	6 years 2 months 8 days	6 years 1 month 24 days	6 years 1 month 24 days	6 years 2 months 15 days
Expected dividend yield	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%
Risk-free interest rate	4.29%	3.02%	4.16%	2.13%	2.13%	1.19%

Subsequent Events (Q3) (Details) $ / shares in Units, $ in Thousands	Oct. 17, 2023 USD ($) Warrant $ / shares shares	Sep. 30, 2023 $ / shares	Jun. 30, 2023 $ / shares	Feb. 24, 2023 $ / shares	Dec. 31, 2022 $ / shares	Dec. 31, 2021 $ / shares
Stockholders' equity [Abstract]
Preferred stock, par value (in dollars per share)		$ 0.0001			$ 0.0001	$ 0.0001
Warrant exercise price per share (in dollars per share)			$ 0
Subsequent Event [Member]
Stockholders' equity [Abstract]
Warrant exercise price per share (in dollars per share)				$ 0
Gross proceeds before underwriting discounts and commissions and offering expenses \| $	$ 2,250
Subsequent Event [Member] \| October 2023 Warrants [Member]
Stockholders' equity [Abstract]
Purchase price for one unit (in dollars per share)	$ 15
Subsequent Event [Member] \| Series J Convertible Preferred Stock [Member]
Stockholders' equity [Abstract]
Issuance of stock (in shares) \| shares	150,000
Number of shares in one unit (in shares) \| shares	1
Preferred stock, par value (in dollars per share)	$ 0.0001
Liquidation preference per share (in dollars per share)	$ 25
Stock term	3 years
Conversion price (in dollars per share)	$ 1.01
Preferred stock, dividend rate	5.00%
Dividend payment period	3 years
Subsequent Event [Member] \| Series J Convertible Preferred Stock [Member] \| October 2023 Warrants [Member]
Stockholders' equity [Abstract]
Number of warrants included in each unit \| Warrant	1
Number of shares to be purchased with each warrant (in shares) \| shares	0.5
Warrants term	3 years
Warrant exercise price per share (in dollars per share)	$ 7.5
Warrant percentage of public offering price per unit	50.00%

Fair Value of Financial Instruments (FY) (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2023

Dec. 31, 2022

Available-for-Sale Marketable Securities Measured at Fair Value on Recurring Basis

The available-for-sale marketable securities primarily consist of investment-grade, U.S.-dollar-denominated fixed and floating rate debt, measured at fair value on a recurring basis.

Marketable securities

$569

The available-for-sale marketable securities primarily consist of investment-grade, U.S. dollar-denominated fixed and floating-rate debt, measured at fair value on a recurring basis.

	2022		2021
(Dollars in thousands)	Fair Value	Level 1	Fair Value	Level 1
Marketable securities	$569	$569	$15,463	$15,463

Roll-Forward of Fair Value of Level 3 Warrants

The following is a roll-forward of the fair value of the Level 3 warrants:

(in thousands)
Balance at December 31, 2022			$6,868
Change in fair value			755
Balance at January 4, 2023 (revaluation date)			7,623
Warrants reclassified to equity			(7,623)
Balance at September 30, 2023			$—

The following is a roll-forward of the fair value of Level 3 warrants:

(in thousands)
October 18, 2022 warrant issuance			$18,695
Change in fair value			(11,827)
Ending balance December 31, 2022			$6,868

Fair Value Assumptions

Fair values were calculated using the following assumptions:

	Oct. 18, 2022	Dec. 31, 2022
Risk-free interest rates, adjusted for continuous compounding	4.16%	3.97%
Term (years)	6.18	6.11
Expected volatility	141.5%	145.3%
Dates and probability of future equity raises	various	various

Operating Leases (FY)

9 Months Ended

12 Months Ended

Sep. 30, 2023

Dec. 31, 2022

Operating Leases [Abstract]

Operating Leases

Note 7 — Operating Leases

The Company leases a 23,000 square foot facility located in Eden Prairie, Minnesota for office and manufacturing space under a non-cancelable operating lease that expires in March 2027. In November 2021, the Company entered into a fourth amendment to the lease, extending the term of the lease from March 31, 2022 to March 31, 2027. This facility serves as our corporate headquarters and houses substantially all our functional departments. Monthly rent and common area maintenance charges, including estimated property tax for our headquarters, total approximately $32,000. The lease contains provisions for annual inflationary adjustments. Rent expense is being recorded on a straight-line basis over the term of the lease. Beginning on April 1, 2022, the annual base rent was $10.50 per square foot, subject to future annual increases of $0.32 to $0.34 per square foot.

Note 8—Operating Leases

The Company leases a 23,000 square foot facility located in Eden Prairie, Minnesota for office and manufacturing space under a non-cancelable operating lease that expires in March 2027. In November 2021, the Company entered into a fourth amendment to the lease, extending the term of the lease from March 31, 2022 to March 31, 2027. This facility serves as our corporate headquarters and houses substantially all our functional areas. Monthly rent and common area maintenance charges, including estimated property tax for our headquarters, total approximately $31,000. The lease contains provisions for annual inflationary adjustments. Rent expense is being recorded on a straight-line basis over the term of the lease. Beginning on April 1, 2022, the annual base rent was $10.50 per square foot, subject to annual increases of $0.32 to $0.34 per square foot thereafter.

The cost components of the Company’s operating lease were as follows for the year ended December 31:

(in thousands)	2022	2021
Operating lease cost	$238	$219
Variable lease cost	127	123
Total	$365	$342

Variable lease costs consist primarily of taxes, insurance, and common area or other maintenance costs for our leased office and manufacturing space.

Maturities of our lease liability for the Company’s operating lease are as follows as of December 31:

(in thousands)			2022
2023			$249
2024			257
2025			264
2026			272
2027			69
Total lease payments			1,111
Less: Interest			(155)
Present value of lease liability			$956

As of December 31, 2022, and 2021, the remaining lease terms were 4.25 and 5.25 years, respectively, and discount rates were 6.25% and 7.5% respectively. For the years ended December 31, 2022, and 2021, the operating cash outflows from the Company’s operating lease for office and manufacturing space were $238,000 and $219,000, respectively.

Income Taxes (FY)

9 Months Ended

12 Months Ended

Sep. 30, 2023

Dec. 31, 2022

Income Taxes [Abstract]

Income Taxes

Note 6 — Income Taxes

As of September 30, 2023, there were no material changes to what the Company disclosed regarding tax uncertainties or penalties in its Annual Report on Form 10-K for the year ended December 31, 2022.

Note 7—Income Taxes

Domestic and foreign income (loss) before income taxes consists of the following for the years ended December 31:

(in thousands)	2022	2021
Domestic	$(14,551)	$(19,582)
Foreign	35	37
Loss before income taxes	$(14,516)	$(19,545)

The components of income tax expense consist of the following for the years ended December 31:

(in thousands)	2022	2021
Current:
United States and state	$—	$—
Foreign, net	(9)	(9)
Deferred:
United States and state	—	—
Foreign	—	—
Total income tax expense	$(9)	$(9)

Actual income tax expense differs from statutory federal income tax expense as follows for the years ended December 31:

(in thousands)	2022	2021
Statutory federal income tax benefit	$3,048	$4,109
State tax benefit, net of federal taxes	783	560
Foreign tax	(1)	(1)
Nondeductible/nontaxable items	548	(220)
Other	(41)	406
Valuation allowance (increase) decrease	(4,346)	(4,863)
Total income tax expense	$(9)	$(9)

Deferred taxes consist of the following as of December 31:

(in thousands)	2022	2021
Deferred tax assets:
Noncurrent:
Accrued leave	$397	$59
Stock based compensation	360	368
Net operating loss carryforward	45,405	42,363
Other	42	131
Intangibles	1,786	723
R&D credit carryforward	531	531
Total deferred tax assets	48,521	44,175
Less: valuation allowance	(48,521)	(44,175)
Total	$—	$—

Stockholders' Equity (Q3)	9 Months Ended	12 Months Ended
Stockholders' Equity (Q3)	Sep. 30, 2023	Dec. 31, 2022
Stockholders' Equity [Abstract]
Stockholders' Equity	Note 3 — Stockholders’ Equity Series F Convertible Preferred Stock: On November 27, 2017, the Company closed on an underwritten public offering of Series F convertible preferred stock and warrants to purchase shares of common stock for gross proceeds of $18.0 million. Net proceeds totaled approximately $16.2 million after deducting the underwriting discounts and commissions and other costs associated with the offering. The offering was comprised of Series F convertible preferred stock, convertible into shares of the Company’s common stock at a conversion price of $189,000 per share. Each share of Series F convertible preferred stock was accompanied by a Series 1 warrant, which expired on the first anniversary of its issuance, to purchase 16 shares of the Company’s common stock at an exercise price of $189,000 per share, and a Series 2 warrant, which expires on the seventh anniversary of its issuance, to purchase 4 shares of the Company’s common stock at an exercise price of $189,000 per share. The Series F convertible preferred stock has full ratchet price-based anti-dilution protection, subject to customary carve-outs, in the event of a down-round financing at a price per share below the conversion price of the Series F convertible preferred stock (which protection will expire if, during any 20 of 30 consecutive trading days, the volume weighted average price of the Company’s common stock exceeds 300% of the then-effective conversion price of the Series F convertible preferred stock and the daily dollar trading volume for each trading day during such period exceeds $200,000). The exercise price of the warrants is fixed and does not contain any variable pricing features, nor any price-based anti-dilutive features, apart from customary adjustments for stock splits, combinations, reclassifications, stock dividends or fundamental transactions. A total of 18,000 shares of Series F convertible preferred stock convertible into 96 shares of common stock and warrants to purchase 191 shares of common stock were issued in the offering. Effective March 12, 2019, the conversion price of the Series F convertible preferred stock was reduced from $89,040 to $15,750, the per share price to the public of the Series G convertible preferred stock issued in the March 2019 Offering. Effective October 25, 2019, the conversion price of the Series F convertible preferred stock was reduced from $15,750 to $4,230, and on November 6, 2019, from $4,230 to $2,983, the per share price to the public in the October and November 2019 transactions, respectively. Effective January 28, 2020, the conversion price of the Series F convertible preferred stock was reduced from $2,983 to $1,650, the per share price to the public of the Series H convertible preferred stock which closed in an underwritten public offering on January 28, 2020. Effective March 23, 2020, the conversion price of the Series F convertible preferred stock was reduced from $1,650 to $900, the per share price to the public in the March 2020 transaction. In connection with the March 2021 Offering, the conversion price of the Series F convertible preferred stock was reduced from $900 to $550, the per share price to the public in the March 2021 Offering. In addition, the exercise price of the common stock warrants issued in connection with the offering consummated by the Company on January 28, 2020 (the “January 2020 Offering”) was reduced from $900 to $550, the per share price to the public in the March 2021 Offering. In connection with the September 2021 offering, the conversion price of the Series F convertible preferred stock was reduced from $550 to $250, the per share price to the public in the September 2021 offering, described below. In connection with the October 2022 offering, the conversion price of the Series F convertible preferred stock was reduced from $250 to $25, the per share price to the public in the October 2022 offering, described below. As of September 30, 2023, and December 31, 2022, 127 shares of the Series F convertible preferred stock remained outstanding. March 2021 Offering: On March 19, 2021, the Company closed on an underwritten public offering of 37,958 shares of common stock, for gross proceeds of approximately $20.9 million (the “March 2021 Offering”). Net proceeds totaled approximately $18.9 million after deducting the underwriting discounts and commissions and other costs associated with the offering and after giving effect to the underwriters’ full exercise of their overallotment option. September 2021 Offering: On September 17, 2021, the Company closed on an underwritten public offering of 40,056 shares of common stock, for gross proceeds of approximately $10.0 million (the “September 2021 Offering”). Net proceeds totaled approximately $9.0 million after deducting the underwriting discounts and commissions and other costs associated with the offering and after giving effect to the underwriters’ full exercise of their overallotment option. In connection with the September 2021 Offering, the conversion price of the Series F convertible preferred stock was reduced from $550 to $250, the per share price to the public in the September 2021 Offering. In addition, the exercise price of the common stock warrants issued in connection with the January 2020 Offering was reduced from $550 to $250, the per share price to the public in the September 2021 Offering. October 2022 Offering: On October 18, 2022, the Company closed on an underwritten public offering of 209,940 shares of common stock and 23,157,124 shares of Series I convertible preferred stock, for gross proceeds of approximately $11.0 million (the “October 2022 Offering”). Net proceeds totaled approximately $9.4 million after deducting underwriting discounts and commissions and other costs associated with the offering and after giving effect to the underwriters’ full exercise of their overallotment option. The offering was comprised of (1) 209,940 Class A Units, priced at a public offering price of $25 per Class A Unit, with each Class A Unit consisting of one share of common stock and 1.5 warrants to purchase one share of common stock at an exercise price of $25 per share, and (2) 23,157,124 Class B Units, priced at a public offering price of $0.25 per Class B Unit, with each Class B Unit consisting of one share of Series I convertible preferred stock, convertible into one share of common stock for every one hundred shares of Series I convertible preferred stock, and 1.5 warrants to purchase one share of common stock for every one hundred shares of Series I convertible preferred stock. The warrants included a cashless exercise provision that upon becoming exercisable, the warrant holders could exercise the warrants for common stock at a zero-dollar exercise price. The warrants became exercisable beginning on the effective date of a reverse stock split in an amount sufficient to permit the exercise in full of the warrants, contingent upon stockholder approval of (i) such reverse stock split and (ii) of the exercisability of the warrants under Nasdaq rules, and they expire on the sixth anniversary of the initial exercise date. On December 8, 2022, following a special meeting of stockholders, the Company’s board of directors approved a one-for-one hundred reverse stock split of the Company’s issued and outstanding shares of common stock (the “Reverse Stock Split”). On December 9, 2022, the Company filed with the Secretary of State of the State of Delaware a Certificate of Amendment to its Certificate of Incorporation to effect the Reverse Stock Split. The Reverse Stock Split became effective as of 5:00 p.m. Eastern Time on December 9, 2022, and the Company’s common stock began trading on a split-adjusted basis when the market opened on December 12, 2022. The conversion price of the preferred stock issued in the October 2022 offering was fixed and does not contain any variable pricing feature or any price-based anti-dilutive feature. The preferred stock issued in this transaction includes a beneficial ownership blocker but has no dividend rights (except to the extent that dividends are also paid on the common stock) or liquidation preference and, subject to limited exceptions, has no voting rights. The securities comprising the units are immediately separable and were issued separately. This reverse stock split did not change the par value of the Company’s common stock or the number of common or preferred shares authorized by the Company’s Fourth Amended and Restated Certificate of Incorporation, as amended. All share and per-share amounts in this quarterly report have been retroactively adjusted to reflect the reverse stock splits for all periods presented. On January 4, 2023, the Company secured stockholder approval for the exercisability of the common stock warrants issued in the October 2022 Offering. The warrants were subsequently determined to be equity-classified warrants and were marked to market, then reclassified to the equity section of the consolidated balance sheet. Through June 30, 2023, 660,046 common stock warrants had converted into 660,046 shares of common stock at a zero-dollar exercise price, with no proceeds received by the Company. In connection with the October 2022 Offering, the conversion price of the Series F convertible preferred stock was reduced from $250 to $25, the per share price to the public in the October 2022 Offering. In addition, the exercise price of the common stock warrants issued in connection with the January 2020 Offering was reduced from $250 to $25, the per share price to the public in the October 2022 Offering. 2023 At-the-Market Program: In March 2023, the Company filed a Prospectus Supplement to its Registration Statement on Form S-3 with the SEC in connection with a proposed At-the-Market Securities offering (the “At-the-Market Program”). During the three months and nine months ended September 30, 2023, the Company issued none and 657,333 shares of common stock under the At-the-Market Program for gross proceeds of none and approximately $2.3 million, respectively. Net proceeds for the three and nine months ended September 30, 2023, totaled none approximately $2.1 million, respectively, after deducting the underwriting discounts and commissions and other costs associated with the offering. Underwriter and Placement Agent Fees: In connection with the offerings described above, the Company paid the underwriter or placement agent, as applicable, an aggregate cash fee equal to 8% of the aggregate gross proceeds raised in each of the offerings, except with respect to the issuances made pursuant to the At-the-Market Program, for which the placement fee was equal to 3% of the aggregate gross proceeds. Market-Based Warrants: On May 30, 2019, the Company granted a market-based warrant to a consultant in exchange for investor relations services. The warrant represents the right to acquire up to 33 shares of the Company’s common stock at an exercise price of $9,540 per share, based on the closing stock price of the Company’s common shares on May 30, 2019. The warrant is subject to a vesting schedule based on the Company achieving certain market stock prices within a specified period of time. The warrant expires on May 30, 2024 and had not vested as of September 30, 2023. Supply Agreement Warrants: On June 19, 2023, we entered into a Supply and Collaboration Agreement (the “Supply Agreement”) with DaVita Inc., a Delaware corporation (“DaVita”), pursuant to which DaVita will pilot the Aquadex ultrafiltration therapy system to treat adult patients with congestive heart failure and related conditions within select U.S. markets. The pilot program is expected to launch by the end of fourth quarter 2023 and extend through May 31, 2024 (the “Pilot”). Through the Pilot, ultrafiltration therapy using Aquadex will be offered at a combination of DaVita’s hospital customer and outpatient center locations, with both companies collaborating on the roll-out of the therapy, clinician training, and patient support. At the conclusion of the Pilot, DaVita has the option, in its sole discretion, to extend the Supply Agreement with the Company for continued provision of both inpatient and outpatient ultrafiltration services for up to 10 years (“Ultrafiltration Services Approval”). In conjunction with the Supply Agreement, the Company issued DaVita a warrant to purchase up to an aggregate of 1,289,081 shares of common stock of the Company, par value $0.0001 per share, at an exercise price of $3.2996 per share (the “DaVita Warrant”), provided that at no time can the DaVita Warrant be exercised for an amount of shares that would represent greater than 19.9% ownership in the Company subject to certain vesting milestones. The DaVita Warrant is expected to vest in four tranches as follows: (i) 25% upon receipt of notice to extend the Supply Agreement past the initial pilot-term; (ii) 25% upon the attainment by the Company of a net revenue achievement from DaVita’s efforts pursuant to the Supply Agreement within twelve months of Ultrafiltration Services Approval; (iii) 25% upon the attainment by the Company of a net revenue achievement from DaVita’s efforts pursuant to the Supply Agreement within twenty-four months of Ultrafiltration Services Approval; and (iv) 25% upon the attainment by the Company of a net revenue achievement from DaVita’s efforts pursuant to the Supply Agreement within thirty-six months of Ultrafiltration Services Approval. This warrant had not vested as of September 30, 2023. The Company evaluated the accounting treatment for the DaVita Warrant pursuant to ASC 718, “Stock Compensation,” and ASC 480, “Distinguishing Liabilities from Equity,” and concluded that the DaVita Warrant should be classified as an equity instrument on the balance sheet as of September 30, 2023. In accordance with this treatment, the Company’s management concluded none of the performance-based vesting conditions of the DaVita warrant were probable of vesting as of September 30, 2023, and therefore, no expense associated with the DaVita Warrant was recognized in the Company’s financial statements as of that date. The Company will continue to evaluate the probability of achieving the performance milestones associated with the DaVita Supply Agreement and will record the related equity-based expense in its financial statements based on the grant date fair value of the DaVita Warrant when management deems it is probable that the performance-based vesting conditions will be achieved.	Note 4—Stockholders’ Equity Series F Convertible Preferred Stock: On November 27, 2017, the Company closed on an underwritten public offering Series F Convertible Preferred Stock and warrants to purchase shares of common stock for gross proceeds of $18.0 million. Net proceeds totaled approximately $16.2 million after deducting the underwriting discounts and commissions and other costs associated with the offering. The offering was comprised of Series F convertible preferred stock, convertible into shares of the Company’s common stock at a conversion price of $189,000 per share. Each share of Series F convertible preferred stock was accompanied by a Series 1 warrant, which was to expire on the first anniversary of its issuance, to purchase 16 shares of the Company’s common stock at an exercise price of $189,000 per share, and a Series 2 warrant, which expires on the seventh anniversary of its issuance, to purchase 4 shares of the Company’s common stock at an exercise price of $189,000 per share. The Series F convertible preferred stock has full ratchet price-based anti-dilution protection, subject to customary carve-outs, in the event of a down-round financing at a price per share below the conversion price of the Series F convertible preferred stock (which protection will expire if, during any 20 of 30 consecutive trading days, the volume weighted average price of the Company’s common stock exceeds 300% of the then-effective conversion price of the Series F convertible preferred stock and the daily dollar trading volume for each trading day during such period exceeds $200,000). The exercise price of the warrants is fixed and does not contain any variable pricing features, nor any price based anti-dilutive features, apart from customary adjustments for stock splits, combinations, reclassifications, stock dividends or fundamental transactions. A total of 18,000 shares of Series F convertible preferred stock convertible into 96 shares of common stock and warrants to purchase 191 shares of common stock were issued in the offering. Effective March 12, 2019, the conversion price of the Series F convertible preferred stock was reduced from $89,040 to $15,750, the per share price to the public of the Series G convertible preferred stock issued in the March 2019 Offering. Effective October 25, 2019, the conversion price of the Series F convertible preferred stock was reduced from $15,750 to $4,230, and on November 6, 2019, from $4,230 to $2,983, the per share price to the public in the October and November 2019 transactions, respectively. Effective January 28, 2020, the conversion price of the Series F convertible preferred stock was reduced from $2,983 to $1,650, the per share price to the public of the Series H convertible preferred stock which closed in an underwritten public offering on January 28, 2020, described below. Effective March 23, 2020, the conversion price of the Series F convertible preferred stock was reduced from $1,650 to $900, the per share price to the public in the March 2020 transaction, described below. In connection with the September 2021 offering, the conversion price of the Series F convertible preferred stock was reduced from $550 to $250, the per share price to the public in the September 2021 offering, described below. In connection with the October 2022 offering, the conversion price of the Series F convertible preferred stock was reduced from $250 to $25, the per share price to the public in the October 2020 offering, described below. As of December 31, 2022, and December 31, 2021, 127 shares of the Series F convertible preferred stock remained outstanding. Series H Convertible Preferred Stock and January 2020 Offering: On January 28, 2020, the Company closed on an underwritten public offering of common stock, Series H convertible preferred stock, and warrants to purchase shares of common stock for gross proceeds of $9.7 million, which included the full exercise of the underwriter’s over-allotment option to purchase additional shares and warrants (“January 2020 Offering”). Net proceeds totaled approximately $8.6 million after deducting the underwriting discounts and commissions and other costs associated with the offering. The Series H convertible preferred stock included a beneficial conversion amount of $1.6 million, representing the intrinsic value of the shares at the time of issuance, and $0.2 million of down-round protection in connection with the re-pricing of the warrants following the March 2020 offering described below. This amount is reflected as an increase to the loss per share allocable to common stockholders in the year ended December 31, 2020. The January 2020 Offering was comprised of 2,015 shares of common stock priced at $1,650 per share and 115,173 shares of Series H convertible preferred stock, convertible into common stock at $1,650 per share, including the full exercise of the over-allotment option. Each share of Series H convertible preferred stock and each share of common stock was accompanied by a warrant to purchase common stock. The warrants are exercisable into 5,855 shares of common stock. The conversion price of the preferred stock issued in the transaction is fixed and does not contain any variable pricing feature or any price-based anti-dilutive feature. The preferred stock issued in this transaction includes a beneficial ownership blocker but has no dividend rights (except to the extent that dividends are also paid on the common stock) or liquidation preference, and, subject to limited exceptions, has no voting rights. The securities comprising the units are immediately separable and were issued separately. The warrants were exercisable beginning on the closing date and expire on the fifth anniversary of the closing date and had an initial exercise price per share equal to $1,650 per share, subject to appropriate adjustment in the event of subsequent equity sales of common stock or securities convertible into common stock for an exercise price per share less than the exercise price per share of the warrants then in effect (but in no event lower than 10% of the applicable unit offering price), or in the event of recapitalization events, stock dividends, stock splits, stock combinations, reclassifications, reorganizations or similar events affecting our common stock. Effective March 23, 2020, the exercise price of these warrants was reduced from $1,650 to $900, the per share price to the public in the March 2020 offering, described below. As of December 31, 2020, all 115,173 shares of the Series H convertible preferred stock had been converted into common stock and none remained outstanding. As of December 31, 2020, warrants to purchase 4,552 shares of common stock had been exercised for total cash proceeds of $4.1 million. March 2020 Offering: On March 23, 2020, the Company closed on a registered direct offering of 1,387 shares of its common stock at a price to the public of $900 per share, for gross proceeds of approximately $1.2 million, or $1.0 million net proceeds, after deducting commissions and offering expenses. In a concurrent private placement, the Company agreed to issue to the investors in the registered direct offering warrants to purchase up to 1,387 shares of the Company’s common stock. The warrants to purchase up to 1,387 shares of common stock have an exercise price of $1,118 per share, were exercisable six months from the date of issuance, and will expire five and a half years from the date of issuance. April 2020 Offering: On April 1, 2020, the Company closed on a registered direct offering of 1,710 shares of its common stock at a price to the public of $1,302 per share, for gross proceeds of approximately $2.2 million, prior to deduction of commissions and offering expenses related to the transaction. In a concurrent private placement, the Company agreed to issue to the investors in the registered direct offering warrants to purchase up to 855 shares of the Company’s common stock. The warrants have an exercise price of $1,115 per share, were exercisable immediately, and will expire five and a half years from the date of issuance. May 2020 Offering: On May 5, 2020, the Company closed on a registered direct offering of 1,199 shares of its common stock at a price to the public of $1,418 per share, for gross proceeds of approximately $1.7 million, prior to deduction of commissions and offering expenses related to the transaction. In a concurrent private placement, the Company agreed to issue to the investors in the registered direct offering warrants to purchase up to 600 shares of the Company’s common stock. The warrants have an exercise price of $1,230 per share, were exercisable immediately, and will expire five and a half years from the date of issuance. August 2020 Offering: On August 21, 2020, the Company closed on an underwritten public offering of common stock and warrants to purchase shares of common stock for gross proceeds of approximately $14.4 million, which included the full exercise of the underwriter’s over-allotment option to purchase additional shares and warrants (“August 2020 Offering”). Net proceeds totaled approximately $13.0 million after deducting the underwriting discounts and commissions and other costs associated with the offering. The August 2020 Offering was comprised of 10,647 shares of common stock priced at $1,350 per share. Each share of common stock was accompanied by a warrant to purchase common stock. The warrants are exercisable into 10,647 shares of common stock. The securities comprising the units are immediately separable and were issued separately. The warrants were exercisable beginning on the effective date of our stockholders’ approval of a reverse stock split in an amount sufficient to permit the exercise in full of the warrants, which occurred on October 6, 2020, and will expire on the five-year anniversary of the closing date. March 2021 Offering: On March 19, 2021, the Company closed on an underwritten public offering of 37,958 shares of common stock, for gross proceeds of approximately $20.9 million (the “March 2021 Offering”). Net proceeds totaled approximately $18.9 million after deducting the underwriting discounts and commissions and other costs associated with the offering and after giving effect to the underwriters’ full exercise of their overallotment option. In connection with the March 2021 Offering, the conversion price of the Series F convertible preferred stock was reduced from $900 to $550, the per share price to the public in the March 2021 Offering. In addition, the exercise price of the common stock warrants issued in connection with the January 2020 Offering was reduced from $900 to $550, the per share price to the public in the March 2021 Offering. September 2021 Offering: On September 17, 2021, the Company closed on an underwritten public offering of 40,056 shares of common stock, for gross proceeds of approximately $10.0 million (the “September 2021 Offering”). Net proceeds totaled approximately $9.0 million after deducting the underwriting discounts and commissions and other costs associated with the offering and after giving effect to the underwriters’ full exercise of their overallotment option. In connection with the September 2021 Offering, the conversion price of the Series F convertible preferred stock was reduced from $550 to $250, the per share price to the public in the September 2021 Offering. In addition, the exercise price of the common stock warrants issued in connection with the January 2020 Offering was reduced from $550 to $250, the per share price to the public in the September 2021 Offering. October 2022 Offering: On October 18, 2022, the Company closed on an underwritten public offering of 209,940 shares of common stock and 23,157,124 shares of Series I convertible preferred stock, for gross proceeds of approximately $11.0 million (the “October 2022 Offering”). Net proceeds totaled approximately $9.4 million after deducting underwriting discounts and commissions and other costs associated with the offering and after giving effect to the underwriters’ full exercise of their overallotment option. The offering was comprised of (1) 209,940 Class A Units, priced at a public offering price of $25 per Class A Unit, with each Class A Unit consisting of one share of common stock for every one hundred shares of Series I convertible preferred stock and 1.5 warrants to purchase one share of common stock at an exercise price of $25 per share, and (2) 23,157,124 Class B Units, priced at a public offering price of $0.25 per Class B Unit, with each Class B Unit consisting of one share of Series I convertible preferred stock, convertible into one share of common stock for every one hundred shares of Series I convertible preferred stock, and 1.5 warrants to purchase one share of common stock for every one hundred shares of Series I convertible preferred stock. The warrants included a cashless exercise provision that upon becoming exercisable, the warrant holders could exercise at a $0.00 exercise price. The warrants became exercisable beginning on the effective date of a reverse stock split in an amount sufficient to permit the exercise in full of the warrants, contingent upon stockholder approval of such reverse stock split and of the exercisability of the warrants under Nasdaq rules, and will expire on the sixth anniversary of the initial exercise date. On December 8, 2022, following a special meeting of stockholders, the Company’s board of directors approved a one-for-one hundred reverse stock split of the Company’s issued and outstanding shares of common stock (the “Reverse Stock Split”). On December 9, 2022, the Company filed with the Secretary of State of the State of Delaware a Certificate of Amendment to its Certificate of Incorporation (the “Certificate of Amendment”) to effect the Reverse Stock Split. The Reverse Stock Split became effective as of 5:00 p.m. Eastern Time on December 9, 2022, and the Company’s common stock began trading on a split-adjusted basis when the market opened on December 12, 2022. The conversion price of the preferred stock issued in the transaction was fixed and does not contain any variable pricing feature or any price-based anti-dilutive feature. The preferred stock issued in this transaction includes a beneficial ownership blocker but has no dividend rights (except to the extent that dividends are also paid on the common stock) or liquidation preference and, subject to limited exceptions, has no voting rights. The securities comprising the units are immediately separable and were issued separately. In connection with the October 2022 Offering, the conversion price of the Series F convertible preferred stock was reduced from $250 to $25, the per share price to the public in the October 2022 Offering. In addition, the exercise price of the common stock warrants issued in connection with the January 2020 Offering was reduced from $250 to $25, the per share price to the public in the October 2022 Offering. Placement Agent Fees: In connection with the offerings described above, the Company paid the placement agents an aggregate cash placement fee equal to 8% of the aggregate gross proceeds raised in each of the offerings. Market-Based Warrants: On May 30, 2019, the Company granted a market-based warrant to a consultant in exchange for investor relations services. The warrant represents the right to acquire up to 33 shares of the Company’s common stock at an exercise price of $9,540 per share, the closing stock price of the Company’s common shares on May 30, 2019. The warrant is subject to a vesting schedule based on the Company achieving certain market stock prices within a specified period of time. The warrant expires on May 30, 2024. None of these warrants had vested as of December 31, 2022. Reverse Stock Split: On December 5, 2022, the Company’s stockholders approved the Company’s management to execute a reverse split of its outstanding common stock at a ratio in the range of 1-for-50 to 1-for-100 and, on December 8, 2022, the Company’s board of directors approved a 1-for-100 reverse split of the Company’s outstanding common stock that became effective after trading on December 9, 2022. This reverse stock split did not change the par value of the Company’s common stock or the number of common or preferred shares authorized by the Company’s Fourth Amended and Restated Certificate of Incorporation, as amended. All share and per-share amounts have been retroactively adjusted to reflect the reverse stock splits for all periods presented.

The entire disclosure for equity.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481004/946-505-50-6

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480237/815-40-50-6

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480008/505-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(e)(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//505/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-16

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

Nature of Business, Basis of Presentation and Significant Accounting Policies [Abstract]

Finance Lease Liability (Q3)	9 Months Ended	12 Months Ended
Finance Lease Liability (Q3)	Sep. 30, 2023	Dec. 31, 2022
Finance Lease Liability [Abstract]
Finance Lease Liability	Note 8 — Finance Lease Liability In 2020, the Company entered into lease agreements to finance equipment valued at $98,000. The equipment consisted of computer hardware and audio-visual equipment and is included in Property, Plant and Equipment in the accompanying consolidated financial statements. The principal amount under the lease agreements was $93,000 at the date the lease commenced, the implied interest rate is 7.5%, and the term of the lease is 39 months.	Note 9—Finance Lease Liability In 2020, the Company entered into lease agreements to finance equipment valued at $98,000. The equipment consisted of computer hardware and audio-visual equipment and is included in Property, Plant and Equipment in the accompanying consolidated financial statements. The principal amount under the lease agreements was $93,000 at the date the lease commenced, the implied interest rate is 7.5%, and the term of the lease is 39 months.

Related Party Transactions (FY) (Details) - USD ($)	12 Months Ended
Related Party Transactions (FY) (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Related Party Transactions [Abstract]
Amount of related party transactions	$ 0	$ 0

Subsequent Events (Q3)	9 Months Ended	12 Months Ended
Subsequent Events (Q3)	Sep. 30, 2023	Dec. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	Note 10 — Subsequent Events Public Offering: On October 17, 2023, the Company closed on a public offering of 150,000 units (the “Units”), with each Unit consisting of one share of the Company’s Series J Convertible Redeemable Preferred Stock, par value $0.0001 per share, with a liquidation preference of $25.00 per share (the “Series J Convertible Preferred Stock”), and one warrant (the “October 2023 Warrants”) to purchase one-half of one (0.50) share of Series J Convertible Preferred Stock. The purchase price for one Unit was $15.00, which reflects the issuance of the Series J Convertible Preferred Stock with an original issue discount. The Series J Convertible Preferred Stock has a term of three (3) years and is convertible at the option of the holder at any time into shares of the Company’s common stock at a conversion price of $1.01. If any shares of our Series J Convertible Preferred Stock are outstanding at the end of the three-year term, then the Company will promptly redeem all of such outstanding shares of Series J Convertible Preferred Stock on a pro rata basis among all of the holders of Series J Convertible Preferred Stock commencing on the third-year anniversary of the closing date of this offering (the “Mandatory Redemption Date”) in cash, to the extent legally permissible under Delaware law, or, if redemption for cash is not legally permissible in duly authorized, validly issued, fully paid and non-assessable shares of the Company’s common stock equal in number to the quotient obtained by dividing such unpaid amount by the closing price of the Company’s common stock on the Nasdaq on the Mandatory Redemption Date. Dividends on the Series J Convertible Preferred Stock will be paid, if and when declared by the Company’s board of directors, in-kind (“PIK dividends”) in additional shares of Series J Convertible Preferred Stock based on the stated value of $25.00 per share at a dividend rate of 5.0%. The PIK dividends will be paid on a quarterly basis for three (3) years following the closing date to holders of the Series J Convertible Preferred Stock of record at the close of business on October 31, January 31, April 30, and July 31 of each year. The October 2023 Warrants have a term of three (3) years. Each October 2023 Warrant has an exercise price of $7.50 (50.0% of the public offering price per Unit) per one-half of one share (0.5) of Series J Convertible Preferred Stock and is immediately exercisable. The Company is currently evaluating the accounting treatment of the Series J Convertible Preferred Stock and the October 2023 Warrants. The gross proceeds before underwriting discounts and commissions and offering expenses, were approximately $2.25 million. The Company intends to use the net proceeds from the offering for working capital and for general corporate purposes.	Note 14—Subsequent Events On January 4, 2023, shareholder approval was secured by the Company for the issuance of the common stock warrants issued in conjunction with the Company’s October 2022 financing. During 2023, through February 24, 2023, there were 660,046 common stock warrants which had converted into 660,046 shares of common stock at a $0 exercise price with no proceeds received by the Company. At-The-Market Offering On March 3, 2023, we entered into a Sales Agreement with Ladenburg Thalmann & Co. Inc. (“Ladenburg”) to create an at-the-market offering program under which we may offer and sell shares having an aggregate offering price of up to $10.0 million. Ladenburg is entitled to a commission at a fixed commission rate equal to up to 3% of the gross proceeds.

Finance Lease Liability (FY) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2020
Finance Lease Liability [Abstract]
Value of finance lease equipment		$ 98
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]		Property, Plant and Equipment, Net
Principal amount under lease agreement		$ 93
Implied interest rate		7.50%
Finance lease term	39 months	39 months

Nature of Business and Basis of Presentation (Q3) (Policies)

9 Months Ended

12 Months Ended

Sep. 30, 2023

Dec. 31, 2022

Principles of Consolidation

Principles of Consolidation: The accompanying condensed consolidated balance sheet as of December 31, 2022, which has been derived from the consolidated audited financial statements, and the unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 8 of Regulation S-X. Certain information and note disclosures normally included in the audited annual consolidated financial statements have been condensed or omitted pursuant to those rules and regulations. Accordingly, they do not include all of the information necessary for a fair presentation of results of operations, comprehensive loss, financial condition, and cash flows in conformity with U.S. GAAP. In the opinion of management, the condensed consolidated financial statements reflect all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation of the results of the Company for the periods presented. Operating results for interim periods are not necessarily indicative of results that may be expected for the year as a whole. The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues, expenses, and the related disclosures at the date of the consolidated financial statements and during the reporting period. Actual results could differ materially from these estimates.

These condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022.

Going Concern

Going Concern: The Company’s consolidated financial statements have been prepared and presented on a basis assuming it continues as a going concern. During the years ended December 31, 2022 and 2021 and through September 30, 2023, the Company incurred losses from operations and net cash outflows from operating activities as disclosed in the consolidated statements of operations and cash flows, respectively. As of September 30, 2023, the Company had an accumulated deficit of $282.1 million and it expects to incur losses for the immediate future. To date, the Company has been funded by equity financings, and although the Company believes that it will be able to successfully fund its operations, there can be no assurance that it will be able to do so or that it will ever operate profitably. These factors raise substantial doubt about the Company’s ability to continue as a going concern through the next twelve months.

require the Company to succeed in training personnel at hospitals and in outpatient care settings, and effectively and efficiently manufacturing, marketing, and distributing the Aquadex System and related components. There can be no assurance that the Company will succeed in these activities, and it may never generate revenues sufficient to achieve profitability.

During 2022, the Company closed on an underwritten public equity offering for aggregate net proceeds of approximately $9.4 million after deducting the underwriting discounts and commissions and other costs associated with the offering. See Note 3 — Stockholders’ Equity for additional related disclosures. The Company will require additional funding to grow its Aquadex Business, which may not be available on terms favorable to the Company, or at all. The Company may receive those funds from the proceeds from future warrant exercises, issuances of equity securities, or other financing transactions.

On March 3, 2023, we entered into a Sales Agreement with Ladenburg Thalmann & Co. Inc. (“Ladenburg”) to create an at-the-market offering program under which we could offer and sell shares of our common stock having an aggregate offering price of up to $10.0 million. Ladenburg was entitled to a commission at a fixed rate equal to 3% of the gross proceeds. For the three and nine months ending September 30, 2023, the Company issued shares under the at-the-market program for aggregate net proceeds of none and approximately $2.1 million after deducting the underwriting discounts and commissions and other costs associated with the offering.

The Company believes that its existing capital resources will be sufficient to support its operating plan through February 28, 2024. However, the Company will seek to raise additional capital to support its growth or other strategic initiatives through debt, equity or a combination thereof. There can be no assurance we will be successful in raising additional capital.

Going Concern

The Company’s financial statements have been prepared and presented on a basis assuming it continues as a going concern. During the years ended December 31, 2022 and 2021, the Company incurred losses from operations and net cash outflows from operating activities as disclosed in the consolidated statements of operations and cash flows, respectively. As of December 31, 2022, the Company had an accumulated deficit of $267.4 million, and it expects to incur losses for the immediate future. To date, the Company has been funded by equity financings, and although the Company believes that it will be able to successfully fund its operations, there can be no assurance that it will be able to do so or that it will ever operate profitably. These factors raise substantial doubt about the Company’s ability to continue as a going concern through at least twelve months from the report date.

The Company became a revenue-generating company after acquiring the Aquadex Business in August 2016. The Company expects to incur additional losses in the near-term as it grows the Aquadex Business, including investments in expanding its sales and marketing capabilities, purchasing inventory, manufacturing components, investing in clinical research and new product development, and complying with the requirements related to being a U.S. public company. To become and remain profitable, the Company must succeed in expanding the adoption and market acceptance of the Aquadex System. This will require the Company to succeed in training personnel at hospitals and effectively and efficiently manufacturing, marketing, and distributing the Aquadex System and related components. There can be no assurance that the Company will succeed in these activities, and it may never generate revenues sufficient to achieve profitability.

During 2021 and through December 31, 2022, the Company closed on underwritten public equity offerings for aggregate net proceeds of approximately $37.3 million after deducting the underwriting discounts and commissions and other costs associated with the offerings. See Note 4—Stockholders’ Equity for additional related disclosure. The Company will require additional funding to grow its Aquadex Business, which may not be available on terms favorable to the Company, or at all. The Company may receive those funds from the proceeds from future warrant exercises, issuances of equity securities, or other financing transactions.

The Company believes that its existing capital resources will be sufficient to support its operating plan through December 31, 2023. However, the Company may seek to raise additional capital to support its growth or other strategic initiatives through debt, equity, or a combination thereof. There can be no assurance we will be successful in raising additional capital.

Revenue Recognition

Revenue Recognition: The Company recognizes revenue in accordance with Accounting Standards Codification, Topic 606, Revenue from Contracts with Customers, which the Company adopted effective January 1, 2018. Accordingly, the Company recognizes revenue when its customers obtain control of its products or services, in an amount that reflects the consideration that the Company expects to receive in exchange for those goods and services. See Note 2 – Revenue Recognition below for additional disclosures. For the three months ended September 30, 2023, two customers represented 21% and 11% of net sales. For the nine months ended September 30, 2023, two customers each represented 17% and 12% of net sales. For the three months ended September 30, 2022, one customer represented 12% of net sales. For the nine months ended September 30, 2022, two customers each represented 13% and 10% of net sales.

Revenue Recognition

The Company recognizes revenue in accordance with Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers. Accordingly, the Company recognizes revenue when its customers obtain control of its products or services, in an amount that reflects the consideration that the Company expects to receive in exchange for those goods and services. See Note 2 – Revenue Recognition, for additional disclosures. For the year ended December 31, 2022, one customer represented 12.5% of net sales. For the years ended December 31, 2021, two customers represented 12.3% and 10.7% of net sales.

Accounts Receivable

Accounts Receivable: Accounts receivable are unsecured, are recorded at net realizable value, and do not bear interest. The Company makes judgments as to its ability to collect outstanding receivables based upon significant patterns of collectability, historical experience, and management’s evaluation of specific accounts and will provide an allowance for credit losses when collection becomes doubtful. The Company performs credit evaluations of its customers’ financial condition on an as-needed basis. Payment is generally due 30 days from the invoice date and accounts past 30 days are individually analyzed for collectability. When all collection efforts have been exhausted, the account is written off against the related allowance. To date, the Company has not experienced any write-offs or significant deterioration of the aging of its accounts receivable, and therefore, no allowance for doubtful accounts was considered necessary as of September 30, 2023, or December 31, 2022. As of September 30, 2023, three customers represented 17%, 17% and 11% of the accounts receivable balance. As of December 31, 2022, two customers represented 15% and 10% of the total accounts receivable balance.

Accounts Receivable

Accounts receivables are unsecured, recorded at net realizable value, and do not bear interest. The Company makes judgments as to its ability to collect outstanding receivables based upon significant patterns of collectability, historical experience, and management’s evaluation of specific accounts, and it will provide an allowance for credit losses when collection becomes doubtful. The Company performs credit evaluations of its customers’ financial condition on an as-needed basis. Payment is generally due 30 days from the invoice date and accounts past 30 days are individually analyzed for collectability. When all collection efforts have been exhausted, the account is written off against the related allowance. To date the Company has not experienced any write-offs or significant deterioration in the aging of its accounts receivable, and therefore, no allowance for doubtful accounts was considered necessary as of December 31, 2022 or December 31, 2021. As of December 31, 2022, two customers represented 15% and 10% of the total accounts receivable balance. As of December 31, 2021, two customers represented 12% and 11% of the total accounts receivable balance.

Inventories: Inventories represent finished goods purchased from the Company’s suppliers and are recorded as the lower of cost or net realizable value using the first-in, first-out method. Overhead is allocated to manufactured finished goods inventory based on the normal capacity of the Company’s production facilities. Abnormal amounts of overhead, if any, are expensed as incurred. Inventories consisted of the following:

(in thousands)	September 30, 2023	December 31, 2022
Finished Goods	$811	$993
Work in Process	170	204
Raw Materials	1,659	1,609
Inventory Reserves	(304)	(145)
Total	$2,336	$2,661

Inventories

Inventories are recorded at the lower of cost or net realizable value using the first-in, first-out method. Overhead is allocated to manufactured finished goods inventory based on the normal capacity of the Company’s production facilities. Abnormal amounts of overhead, if any, are expensed as incurred. On a regular basis, the Company reviews its inventory and identifies that which is excess, slow moving, and obsolete by considering factors such as inventory levels and expected product life. A reserve is established for any identified excess, slow moving, and obsolete inventory through a charge to cost of goods sold. Inventories consisted of the following as of December 31:

(Dollars in thousands)	2022	2021
Finished Goods	$993	$1,527
Work in Process	204	276
Raw Materials	1,609	1,281
Inventory Reserves	(145)	(241)
Total	$2,661	$2,843

Loss per Share

Loss per Share: Basic loss per share is computed based on the net loss for each period divided by the weighted average number of common shares outstanding. See Note 3 – Stockholders’ Equity below for additional disclosures.

Diluted earnings per share is computed based on the net loss allocable to common stockholders for each period divided by the weighted average number of common shares outstanding, increased by the number of additional shares that would have been outstanding had the potentially dilutive common shares been issued, and reduced by the number of shares the Company could have repurchased from the proceeds from issuance of the potentially dilutive shares. Potentially dilutive shares of common stock include shares underlying outstanding convertible preferred stock, warrants, stock options and other stock-based awards granted under stock-based compensation plans.

The following table sets forth the potential shares of common stock that are not included in the calculation of diluted net loss per share because to do so would be anti-dilutive as of the end of each period presented:

	September 30
	2023	2022
Stock options	111,275	11,910
Warrants to purchase common stock	1,308,271	16,970
Series F convertible preferred stock	5,080	508
Total	1,424,626	29,388

The following table reconciles reported net loss with reported net loss per share for each of the three and nine months ended September 30:

	Three months ended September 30		Nine months ended September 30
(in thousands, except per share amounts)	2023	2022	2023	2022
Net loss	$(3,370)	$(3,870)	$(14,700)	$(12,629)
Weighted average shares outstanding	1,864	105	1,439	105
Basic and diluted loss per share	$(1.81)	$(36.72)	$(10.21)	$(119.85)

Loss per share

Basic loss per share is computed based on the net loss for each period divided by the weighted average number of common shares outstanding. The net loss allocable to common stockholders for the year ended December 31, 2021, includes a deemed dividend of $75,000 that resulted from the change in the exercise price of warrants as a result of the March 2021 and September 2021 public offerings. (see Note 4 — Stockholders’ Equity).

	December 31,
	2022	2021
Stock options	10,485	7,481
Warrants to purchase common stock	679,244	16,299
Series F convertible preferred stock	5,080	50,800
Series I convertible preferred stock	10,493	—
Total	705,302	74,580

The following table reconciles reported net loss with reported net loss per share for the years ended December 31:

(in thousands, except per share amounts)	2022	2021
Net loss	$(14,525)	$(19,545)
Deemed dividend to preferred stockholders (see Note 4)	—	(75)
Net loss after deemed dividend	(14,525)	(19,620)
Weighted average shares outstanding	174	69
Basic and diluted loss per share	$(83.55)	$(285.36)

Subsequent Events

Subsequent Events: The Company evaluates events through the date the consolidated financial statements are filed for events requiring adjustment to or disclosure in the consolidated financial statements. See note 10 – Subsequent Events for additional disclosures.

Disclosure of inventory accounting policy for inventory classes, including, but not limited to, basis for determining inventory amounts, methods by which amounts are added and removed from inventory classes, loss recognition on impairment of inventories, and situations in which inventories are stated above cost.

Disclosure of accounting policy for revenue from contract with customer.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-17

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 19
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-19

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-18

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-18

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 20
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-20

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 20
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-20

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 20
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-20

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 20
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-20

Reference 9: http://www.xbrl.org/2003/role/exampleRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (e)
-SubTopic 10
-Topic 235
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483426/235-10-50-4

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Topic 606
-Publisher FASB
-URI https://asc.fasb.org//606/tableOfContent

Fair Value of Financial Instruments, Available-for-Sale Marketable Securities Measured at Fair Value on Recurring Basis (FY) (Details) - Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2021
Available-for-sale marketable securities [Abstract]
Marketable securities	$ 0	$ 569	$ 15,463
Level 1 [Member]
Available-for-sale marketable securities [Abstract]
Marketable securities	$ 0	$ 569	$ 15,463

Related Party Transactions (FY)	12 Months Ended
Related Party Transactions (FY)	Dec. 31, 2022
Related Party Transactions [Abstract]
Related Party Transactions	Note 11—Related Party Transactions There were no related party transactions requiring disclosure during the year ended December 31, 2022 and 2021.

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-5

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-6

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(g)(3))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(c))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(e))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//850/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-6

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Nature of Business, Basis of Presentation and Significant Accounting Policies [Abstract]

Consolidated Statements of Stockholders' Equity (FY) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid in Capital [Member]	Accumulated Other Comprehensive Income [Member]	Accumulated Deficit [Member]	Total
Balance at Dec. 31, 2020	$ 0	$ 249,663	$ (7)	$ (233,338)	$ 16,318
Balance (in shares) at Dec. 31, 2020	27,360
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(19,554)	(19,554)
Unrealized foreign currency translation adjustment	0	0	(4)	0	(4)
Unrealized gain (loss) on marketable securities	0	0	(24)	0	(24)
Stock-based compensation, net	$ 0	1,314	0	0	1,314
Stock-based compensation, net (in shares)	0
Issuance of common stock, net	$ 0	27,896	0	0	27,896
Issuance of common stock, net (in shares)	78,014
Exercise of warrants	$ 0	1	0	0	1
Exercise of warrants (in shares)	2
Balance at Dec. 31, 2021	$ 0	278,874	(35)	(252,892)	25,947
Balance (in shares) at Dec. 31, 2021	105,376
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(4,473)	(4,473)
Unrealized foreign currency translation adjustment	0	0	(2)	0	(2)
Stock-based compensation, net	$ 0	241	0	0	241
Stock-based compensation, net (in shares)	0
Balance at Mar. 31, 2022	$ 0	279,115	(37)	(257,365)	21,713
Balance (in shares) at Mar. 31, 2022	105,376
Balance at Dec. 31, 2021	$ 0	278,874	(35)	(252,892)	25,947
Balance (in shares) at Dec. 31, 2021	105,376
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss					(12,629)
Balance at Sep. 30, 2022	$ 0	279,571	(34)	(265,521)	14,016
Balance (in shares) at Sep. 30, 2022	105,376
Balance at Dec. 31, 2021	$ 0	278,874	(35)	(252,892)	25,947
Balance (in shares) at Dec. 31, 2021	105,376
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(14,525)	(14,525)
Unrealized foreign currency translation adjustment	0	0	(7)	0	(7)
Unrealized gain (loss) on marketable securities	0	0	80	0	80
Stock-based compensation, net	$ 0	862	0	0	862
Stock-based compensation, net (in shares)	0
Issuance of common stock, net	$ 0	0	0	0	0
Issuance of common stock, net (in shares)	209,940
Conversion of preferred stock into common stock	$ 0	0	0	0	0
Conversion of preferred stock into common stock (in shares)	221,078
Balance at Dec. 31, 2022	$ 0	279,736	38	(267,417)	12,357
Balance (in shares) at Dec. 31, 2022	536,394
Balance at Mar. 31, 2022	$ 0	279,115	(37)	(257,365)	21,713
Balance (in shares) at Mar. 31, 2022	105,376
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(4,286)	(4,286)
Unrealized foreign currency translation adjustment	0	0	1	0	1
Stock-based compensation, net	$ 0	236	0	0	236
Stock-based compensation, net (in shares)	0
Balance at Jun. 30, 2022	$ 0	279,351	(36)	(261,651)	17,664
Balance (in shares) at Jun. 30, 2022	105,376
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(3,870)	(3,870)
Unrealized foreign currency translation adjustment	0	0	2	0	2
Stock-based compensation, net	$ 0	220	0	0	220
Stock-based compensation, net (in shares)	0
Balance at Sep. 30, 2022	$ 0	279,571	(34)	(265,521)	14,016
Balance (in shares) at Sep. 30, 2022	105,376
Balance at Dec. 31, 2022	$ 0	279,736	38	(267,417)	12,357
Balance (in shares) at Dec. 31, 2022	536,394
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(6,485)	(6,485)
Unrealized foreign currency translation adjustment	0	0	(7)	0	(7)
Unrealized gain (loss) on marketable securities	0	0	6	0	6
Stock-based compensation, net	$ 0	181	0	0	181
Stock-based compensation, net (in shares)	0
Issuance of common stock, net	$ 0	11	0	0	11
Conversion of preferred stock into common stock	$ 0	0	0	0	0
Conversion of preferred stock into common stock (in shares)	10,493
Balance at Mar. 31, 2023	$ 0	287,529	37	(273,902)	13,664
Balance (in shares) at Mar. 31, 2023	1,206,932
Balance at Dec. 31, 2022	$ 0	279,736	38	(267,417)	12,357
Balance (in shares) at Dec. 31, 2022	536,394
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss					(14,700)
Balance at Sep. 30, 2023	$ 0	289,980	(24)	(282,117)	7,839
Balance (in shares) at Sep. 30, 2023	1,864,265
Balance at Mar. 31, 2023	$ 0	287,529	37	(273,902)	13,664
Balance (in shares) at Mar. 31, 2023	1,206,932
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(4,845)	(4,845)
Unrealized foreign currency translation adjustment	0	0	0	0	0
Unrealized gain (loss) on marketable securities	0	0	(61)	0	(61)
Stock-based compensation, net	$ 0	197	0	0	197
Stock-based compensation, net (in shares)	0
Issuance of common stock, net	$ 0	98	0	0	98
Issuance of common stock, net (in shares)	657,333
Balance at Jun. 30, 2023	$ 0	289,845	(24)	(278,747)	11,074
Balance (in shares) at Jun. 30, 2023	1,864,265
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(3,370)	(3,370)
Unrealized foreign currency translation adjustment	0	0	0	0	0
Unrealized gain (loss) on marketable securities	0	0	0	0	0
Stock-based compensation, net	$ 0	135	0	0	135
Stock-based compensation, net (in shares)	0
Issuance of common stock, net	$ 0	0	0	0	0
Issuance of common stock, net (in shares)	0
Balance at Sep. 30, 2023	$ 0	$ 289,980	$ (24)	$ (282,117)	$ 7,839
Balance (in shares) at Sep. 30, 2023	1,864,265

Operating Leases (FY) (Details) $ in Thousands	9 Months Ended	12 Months Ended
Operating Leases (FY) (Details) $ in Thousands	Sep. 30, 2023 USD ($) ft² $ / ft²	Dec. 31, 2022 USD ($) ft² $ / ft²	Dec. 31, 2021 USD ($)
Operating Leases [Abstract]
Area of property leased under operating lease \| ft²	23,000	23,000
Monthly rent and common area maintenance charges	$ 32	$ 31
Annual base rent (per square foot) \| $ / ft²	10.5	10.5
Cost Components of Operating Leases [Abstract]
Operating lease cost		$ 238	$ 219
Variable lease cost		127	123
Total		365	$ 342
Maturities of Lease Liability [Abstract]
2023		249
2024		257
2025		264
2026		272
2027		69
Total lease payments		1,111
Less: Interest		(155)
Present value of lease liability		$ 956
Remaining lease term		4 years 3 months	5 years 3 months
Discount rate		6.25%	7.50%
Operating cash outflows from operating lease		$ 238	$ 219
Minimum [Member]
Operating Leases [Abstract]
Annual increase per square foot (in dollars per square foot) \| $ / ft²	0.32	0.32
Maximum [Member]
Operating Leases [Abstract]
Annual increase per square foot (in dollars per square foot) \| $ / ft²	0.34	0.34

Operating Leases (Q3)

9 Months Ended

12 Months Ended

Sep. 30, 2023

Dec. 31, 2022

Operating Leases [Abstract]

Operating Leases

Note 7 — Operating Leases

Note 8—Operating Leases

The Company leases a 23,000 square foot facility located in Eden Prairie, Minnesota for office and manufacturing space under a non-cancelable operating lease that expires in March 2027. In November 2021, the Company entered into a fourth amendment to the lease, extending the term of the lease from March 31, 2022 to March 31, 2027. This facility serves as our corporate headquarters and houses substantially all our functional areas. Monthly rent and common area maintenance charges, including estimated property tax for our headquarters, total approximately $31,000. The lease contains provisions for annual inflationary adjustments. Rent expense is being recorded on a straight-line basis over the term of the lease. Beginning on April 1, 2022, the annual base rent was $10.50 per square foot, subject to annual increases of $0.32 to $0.34 per square foot thereafter.

The cost components of the Company’s operating lease were as follows for the year ended December 31:

(in thousands)	2022	2021
Operating lease cost	$238	$219
Variable lease cost	127	123
Total	$365	$342

Variable lease costs consist primarily of taxes, insurance, and common area or other maintenance costs for our leased office and manufacturing space.

Maturities of our lease liability for the Company’s operating lease are as follows as of December 31:

(in thousands)			2022
2023			$249
2024			257
2025			264
2026			272
2027			69
Total lease payments			1,111
Less: Interest			(155)
Present value of lease liability			$956

Document and Entity Information	9 Months Ended
Document and Entity Information	Sep. 30, 2023
Cover [Abstract]
Document Type	S-1/A
Amendment Flag	false
Entity Registrant Name	Nuwellis, Inc.
Entity Central Index Key	0001506492
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false

Nature of Business and Basis of Presentation, Nature of Business, Going Concern, Accounts Receivable and Inventories (Q3) (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended		24 Months Ended
	Sep. 30, 2023 USD ($) Customer	Sep. 30, 2022 Customer	Sep. 30, 2023 USD ($) Customer	Sep. 30, 2022 USD ($) Customer	Dec. 31, 2022 USD ($) Customer	Dec. 31, 2021 USD ($) Customer	Dec. 31, 2022 USD ($)	Mar. 03, 2023 USD ($)
Going Concern [Abstract]
Accumulated deficit	$ (282,117)		$ (282,117)		$ (267,417)	$ (252,892)	$ (267,417)
Net proceeds from issuance of public offering				$ 9,400			37,300
Revenue Recognition [Abstract]
Accounts receivables maximum credit period from invoice date			30 days		30 days
Allowance for doubtful accounts	0		$ 0		$ 0	0	0
Inventories [Abstract]
Finished Goods	811		811		993	1,527	993
Work in Process	170		170		204	276	204
Raw Materials	1,659		1,659		1,609	1,281	1,609
Inventory Reserves	(304)		(304)		(145)	(241)	(145)
Total	2,336		2,336		$ 2,661	$ 2,843	$ 2,661
Ladenburg Thalmann & Co. [Member]
Going Concern [Abstract]
Percentage of fixed commission rate								3.00%
Net proceeds from public stock offering	$ 0		$ 2,100
Ladenburg Thalmann & Co. [Member] \| Maximum [Member]
Going Concern [Abstract]
Aggregate offering price								$ 10,000
Accounts Receivable [Member]
Revenue Recognition [Abstract]
Number of major customers \| Customer			3		2	2
Customer One [Member] \| Accounts Receivable [Member] \| Customer Concentration Risk [Member]
Revenue Recognition [Abstract]
Concentration risk percentage			17.00%		15.00%	12.00%
Customer Two [Member] \| Accounts Receivable [Member] \| Customer Concentration Risk [Member]
Revenue Recognition [Abstract]
Concentration risk percentage			17.00%		10.00%	11.00%
Customer Three [Member] \| Accounts Receivable [Member] \| Customer Concentration Risk [Member]
Revenue Recognition [Abstract]
Concentration risk percentage			11.00%
ASC 606 [Member] \| Net Sales [Member]
Revenue Recognition [Abstract]
Number of major customers \| Customer	2	1	2	2	1	2
ASC 606 [Member] \| Customer One [Member] \| Net Sales [Member] \| Customer Concentration Risk [Member]
Revenue Recognition [Abstract]
Concentration risk percentage	21.00%	12.00%	17.00%	13.00%	12.50%	12.30%
ASC 606 [Member] \| Customer Two [Member] \| Net Sales [Member] \| Customer Concentration Risk [Member]
Revenue Recognition [Abstract]
Concentration risk percentage	11.00%		12.00%	10.00%		10.70%

Nature of Business and Significant Accounting Policies (FY) (Policies)

9 Months Ended

12 Months Ended

Sep. 30, 2023

Dec. 31, 2022

Going Concern

Basis of Presentation

The accompanying consolidated financial statements include the accounts of Nuwellis, Inc. and its wholly owned subsidiary, Sunshine Heart Ireland Limited. All intercompany accounts and transactions between consolidated entities have been eliminated.

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts and disclosures in the consolidated financial statements and accompanying notes. Actual results could differ materially from those estimates.

Cash and Cash Equivalents

Cash and cash equivalents consist of cash and term deposits with original maturities of three months or less. The carrying value of these instruments approximates fair value. The balances, at times, may exceed federally insured limits. The Company has not experienced any losses on its cash and cash equivalents.

Marketable securities

The Company’s marketable securities typically consist of investment-grade, U.S. dollar-denominated fixed and floating-rate debt, which are classified as available-for-sale and included in current assets. Most marketable securities mature within twelve months from their date of purchase and generally are intended to fund current operations. Securities are valued based on market prices for similar assets using third party certified pricing sources. Available-for-sale securities are carried at fair value with unrealized gains and losses reported as a component of shareholders’ equity in accumulated other comprehensive income (loss).

Available-for-sale securities are reviewed for possible impairment at least quarterly, or more frequently if circumstances arise that may indicate impairment. When the fair value of the securities declines below the amortized cost basis and impairment is indicated, it must be determined whether the impairment is other than temporary. Impairment is considered to be other than temporary if the Company: (i) intends to sell the security, (ii) will more likely than not be forced to sell the security before recovering its cost, or (iii) does not expect to recover the security’s amortized cost basis. If the decline in fair value is considered other than temporary, the cost basis of the security is adjusted to its fair market value and the realized loss is reported in earnings. Subsequent increases or decreases in fair value are reported as a component of shareholders’ equity in accumulated other comprehensive gain (loss). There were no other than temporary unrealized losses as of December 31, 2022.

Accounts Receivable

Property, Plant and Equipment

(in thousands)	September 30, 2023	December 31, 2022
Finished Goods	$811	$993
Work in Process	170	204
Raw Materials	1,659	1,609
Inventory Reserves	(304)	(145)
Total	$2,336	$2,661

Inventories

(Dollars in thousands)	2022	2021
Finished Goods	$993	$1,527
Work in Process	204	276
Raw Materials	1,609	1,281
Inventory Reserves	(145)	(241)
Total	$2,661	$2,843

Other Current Assets

Other current assets represent prepayments and deposits made by the Company.

Property, plant and equipment is stated at cost less accumulated depreciation. Depreciation is computed based upon the estimated useful life of the respective asset. Leasehold improvements are amortized using the straight-line method over the shorter of the lease term or the estimated useful life of the assets. Repairs and maintenance cost is expensed as incurred. The cost and accumulated depreciation of property, plant and equipment retired or otherwise disposed of is removed from the related accounts, and any residual values are charged to expense. Depreciation expense has been calculated using the following estimated useful lives:

Production Equipment			3-7 years
Office Furniture and Fixtures			3-5 years
Computer Software and Equipment			3-4 years
Loaners and demo equipment			1-5 years
Leasehold improvements			3-5 years

Depreciation expense was $372,000 and $488,000 for the years ended December 31, 2022 and 2021, respectively.

Property, plant and equipment is reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or asset group may not be recoverable. If the impairment tests indicate that the carrying value of the asset or asset group is greater than the expected undiscounted cash flows to be generated by such asset or asset group, further analysis is performed to determine the fair value of the asset or asset group. To the extent the fair value of the asset or asset group is less than its carrying value, an impairment loss is recognized equal to the amount the fair value of the asset or asset group is exceeded by its carrying amount. Assets to be disposed of are carried at the lower of their carrying value or fair value less costs to sell. Considerable management judgment is necessary to estimate the fair value of assets or asset groups, and accordingly, actual results could vary significantly from such estimates.

The Company continues to report operating losses and negative cash flows from operations, both of which it considers to be indicators of potential impairment. Therefore, the Company evaluates its long-lived assets for potential impairment at each reporting period. The Company has concluded that its cash flows from the various long-lived assets are highly interrelated and, as a result, the Company consists of a single asset group. As the Company expects to continue incurring losses in the foreseeable future, the undiscounted cash flow step was bypassed, and the Company proceeded to fair value the asset group. The Company has determined the fair value of the asset group using a combination of expected discounted cash flows and other fair value indicators related to the asset grouping.

There have been no impairment losses recognized for the years ended December 31, 2022 or 2021.

Accounts Payable and Accrued Liabilities

Accrued liabilities includes amounts accrued but not invoiced related to payments owed for licensing agreements, director fees, and others.

Revenue Recognition

Foreign Currency Translation

Sales and expenses denominated in foreign currencies are translated at average exchange rates in effect throughout the year. Assets and liabilities of foreign operations are translated at period-end exchange rates with the impacts of foreign currency translation recorded in cumulative translation adjustment, a component of accumulated other comprehensive income. Foreign currency transactions gains and losses are included in other expense, net in the consolidated statements of operations and other comprehensive loss.

Stock-Based Compensation

The Company recognizes all share-based payments to employees, directors, and consultants, including grants of stock options and common stock awards, in the consolidated statement of operations and comprehensive loss as an operating expense based on their fair values as established at the grant date. Equity instruments issued to non-employees include common stock awards or warrants to purchase shares of our common stock. These common stock awards or warrants are either fully vested and exercisable at the date of grant or vest over a certain period during which services are provided. The Company expenses the fair market value of fully vested awards at the time of grant, and of unvested awards over the period in which the related services are received.

The Company computes the estimated fair values of stock options using the Black-Scholes option pricing model. Market price at the date of grant is used to calculate the fair value of common stock awards.

Stock-based compensation expense is based on awards ultimately expected to vest and is reduced for forfeitures. See Note 5—Stock-Based Compensation, for further information regarding the assumptions used to calculate the fair value of stock-based compensation.

Income Taxes

Deferred income taxes are provided on a liability method, whereby deferred tax assets are recognized for deductible temporary differences and operating loss and tax credit carryforwards. Deferred tax liabilities are recognized for taxable temporary differences, which are the differences between the reported amounts of assets and liabilities and their tax bases. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some portion or all of the deferred tax assets will not be realized. Deferred tax assets and liabilities are adjusted for the effects of changes in tax laws and rates on the date of enactment. The Company recognizes the financial statement benefit of a tax position only after determining that the relevant tax authority would more likely than not sustain the position following an audit. For tax positions meeting the more-likely-than-not threshold, the amount recognized in the consolidated financial statements is the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority.

Loss per Share

	September 30
	2023	2022
Stock options	111,275	11,910
Warrants to purchase common stock	1,308,271	16,970
Series F convertible preferred stock	5,080	508
Total	1,424,626	29,388

The following table reconciles reported net loss with reported net loss per share for each of the three and nine months ended September 30:

	Three months ended September 30		Nine months ended September 30
(in thousands, except per share amounts)	2023	2022	2023	2022
Net loss	$(3,370)	$(3,870)	$(14,700)	$(12,629)
Weighted average shares outstanding	1,864	105	1,439	105
Basic and diluted loss per share	$(1.81)	$(36.72)	$(10.21)	$(119.85)

Loss per share

	December 31,
	2022	2021
Stock options	10,485	7,481
Warrants to purchase common stock	679,244	16,299
Series F convertible preferred stock	5,080	50,800
Series I convertible preferred stock	10,493	—
Total	705,302	74,580

The following table reconciles reported net loss with reported net loss per share for the years ended December 31:

(in thousands, except per share amounts)	2022	2021
Net loss	$(14,525)	$(19,545)
Deemed dividend to preferred stockholders (see Note 4)	—	(75)
Net loss after deemed dividend	(14,525)	(19,620)
Weighted average shares outstanding	174	69
Basic and diluted loss per share	$(83.55)	$(285.36)

Research and Development

Research and development (R&D) costs include activities related to development, design, and testing improvements of the Aquadex System and potential related new products. These R&D costs also include expenses related to clinical research that the Company may sponsor or conduct to enhance understanding of the product and its use. R&D costs are expensed as incurred.

Recent Accounting Pronouncements

In June 2016, the FASB issued Accounting Standards Update (ASU) 2016-13, “Financial Instruments – Credit Losses.” This ASU added a new impairment model (known as the current expected credit loss (“CECL”) model) that is based on expected losses rather than incurred losses. Under the new guidance, an entity recognizes as an allowance its estimate of expected credit losses. The CECL model applies to most debt instruments, trade receivables, lease receivables, financial guarantee contracts, and other loan commitments. The CECL model does not have a minimum threshold for recognition of impairment losses, and entities will need to measure expected credit losses on assets that have a low risk of loss. As a smaller reporting company pursuant to Rule 12b-2 of the Securities Exchange Act of 1934, as amended, these changes become effective for the Company on January 1, 2023. Management has evaluated the potential impact of these changes on the consolidated financial statements of the Company and does not anticipate it will have any impact to the Company’s consolidated financial statements.

The Company evaluates subsequent events through the date the consolidated financial statements are filed for events requiring adjustment to or disclosure in the consolidated financial statements.

Property, Plant and Equipment (FY) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment, Gross [Abstract]
Property, Plant and Equipment, Gross		$ 4,151	$ 4,008
Accumulated Depreciation		(3,171)	(2,820)
Property, Plant and Equipment, Net	$ 912	980	1,188
Production Equipment [Member]
Property, Plant and Equipment, Gross [Abstract]
Property, Plant and Equipment, Gross		1,360	1,321
Loaners and Demo Equipment [Member]
Property, Plant and Equipment, Gross [Abstract]
Property, Plant and Equipment, Gross		1,444	1,364
Computer Software and Equipment [Member]
Property, Plant and Equipment, Gross [Abstract]
Property, Plant and Equipment, Gross		719	714
Office Furniture & Fixtures [Member]
Property, Plant and Equipment, Gross [Abstract]
Property, Plant and Equipment, Gross		375	364
Leasehold Improvements [Member]
Property, Plant and Equipment, Gross [Abstract]
Property, Plant and Equipment, Gross		$ 253	$ 245

Commitments and Contingencies (Q3) (Details) - SeaStar Medical Holding Corporation [Member] - USD ($) $ in Thousands		9 Months Ended
	Dec. 27, 2022	Sep. 30, 2023
Commitments and Contingencies [Abstract]
Milestone payments	$ 450
Payment period after achievement of milestone event		30 days

Nature of Business and Basis of Presentation (Q3) (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2023

Dec. 31, 2022

Nature of Business, Basis of Presentation and Significant Accounting Policies [Abstract]

Potential Shares of Common Stock not Included in Diluted Net Loss Per Share

Inventories consisted of the following:

(in thousands)	September 30, 2023	December 31, 2022
Finished Goods	$811	$993
Work in Process	170	204
Raw Materials	1,659	1,609
Inventory Reserves	(304)	(145)
Total	$2,336	$2,661

Inventories consisted of the following as of December 31:

(Dollars in thousands)	2022	2021
Finished Goods	$993	$1,527
Work in Process	204	276
Raw Materials	1,609	1,281
Inventory Reserves	(145)	(241)
Total	$2,661	$2,843

	September 30
	2023	2022
Stock options	111,275	11,910
Warrants to purchase common stock	1,308,271	16,970
Series F convertible preferred stock	5,080	508
Total	1,424,626	29,388

	December 31,
	2022	2021
Stock options	10,485	7,481
Warrants to purchase common stock	679,244	16,299
Series F convertible preferred stock	5,080	50,800
Series I convertible preferred stock	10,493	—
Total	705,302	74,580

Reconciliation of Reported Net Loss with Reported Net Loss Per Share

The following table reconciles reported net loss with reported net loss per share for each of the three and nine months ended September 30:

	Three months ended September 30		Nine months ended September 30
(in thousands, except per share amounts)	2023	2022	2023	2022
Net loss	$(3,370)	$(3,870)	$(14,700)	$(12,629)
Weighted average shares outstanding	1,864	105	1,439	105
Basic and diluted loss per share	$(1.81)	$(36.72)	$(10.21)	$(119.85)

The following table reconciles reported net loss with reported net loss per share for the years ended December 31:

(in thousands, except per share amounts)	2022	2021
Net loss	$(14,525)	$(19,545)
Deemed dividend to preferred stockholders (see Note 4)	—	(75)
Net loss after deemed dividend	(14,525)	(19,620)
Weighted average shares outstanding	174	69
Basic and diluted loss per share	$(83.55)	$(285.36)

Finance Lease Liability (Q3) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2020
Finance Lease Liability [Abstract]
Value of finance lease equipment		$ 98
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]		Property, Plant and Equipment, Net
Principal amount under lease agreement		$ 93
Implied interest rate		7.50%
Finance lease term	39 months	39 months

Condensed Consolidated Balance Sheets (Q3) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2021
Current assets
Cash and cash equivalents	$ 4,930	$ 17,737	$ 8,742
Marketable securities	0	569	15,463
Accounts receivable	1,425	1,406	750
Inventories, net	2,336	2,661	2,843
Other current assets	947	396	328
Total current assets	9,638	22,769	28,126
Property, plant and equipment, net	912	980	1,188
Operating lease right-of-use asset	762	903	1,082
Other assets	120	21	21
TOTAL ASSETS	11,432	24,673	30,417
Current liabilities
Accounts payable and accrued liabilities	1,707	2,245	1,414
Accrued compensation	1,021	2,161	1,664
Current portion of operating lease liability	211	196	167
Current portion of finance lease liability	8	28	26
Other current liabilities	45	58	36
Total current liabilities	2,992	4,688	3,307
Common stock warrant liability	0	6,868	0
Operating lease liability	601	760	956
Total liabilities	3,593	12,316	4,470
Commitments and contingencies
Stockholders' equity
Preferred stock	0	0	0
Common stock as of September 30, 2023 and December 31, 2022, par value $0.0001 per share; authorized 100,000,000 shares, issued and outstanding 1,864,265 and 536,394 shares, respectively	0	0	0
Additional paid-in capital	289,980	279,736	278,874
Accumulated other comprehensive income:
Foreign currency translation adjustment	(24)	(18)	(11)
Unrealized gain on marketable securities	0	56	(24)
Accumulated deficit	(282,117)	(267,417)	(252,892)
Total stockholders' equity	7,839	12,357	25,947
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	11,432	24,673	30,417
Series A Junior Participating Preferred Stock [Member]
Stockholders' equity
Preferred stock	0	0	0
Series F Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock	0	0	0
Series I Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock	$ 0	$ 0	$ 0

Nature of Business and Significant Accounting Policies, Going Concern, Accounts Receivable and Inventories (FY) (Details) $ in Thousands	9 Months Ended		12 Months Ended		24 Months Ended
	Sep. 30, 2023 USD ($) Customer	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($) Customer	Dec. 31, 2021 USD ($) Customer	Dec. 31, 2022 USD ($)
Going Concern [Abstract]
Accumulated deficit	$ (282,117)		$ (267,417)	$ (252,892)	$ (267,417)
Net proceeds from issuance of public offering		$ 9,400			37,300
Accounts Receivable [Abstract]
Accounts receivables maximum credit period from invoice date	30 days		30 days
Allowance for doubtful accounts	$ 0		$ 0	0	0
Inventories [Abstract]
Finished Goods	811		993	1,527	993
Work in Process	170		204	276	204
Raw Materials	1,659		1,609	1,281	1,609
Inventory Reserves	(304)		(145)	(241)	(145)
Total	$ 2,336		$ 2,661	$ 2,843	$ 2,661
Accounts Receivable [Member]
Revenue, Performance Obligation [Abstract]
Number of major customers \| Customer	3		2	2
Accounts Receivable [Member] \| Customer Concentration Risk [Member] \| Customer One [Member]
Revenue, Performance Obligation [Abstract]
Concentration risk percentage	17.00%		15.00%	12.00%
Accounts Receivable [Member] \| Customer Concentration Risk [Member] \| Customer Two [Member]
Revenue, Performance Obligation [Abstract]
Concentration risk percentage	17.00%		10.00%	11.00%

Segment and Geographic Information (FY)	12 Months Ended
Segment and Geographic Information (FY)	Dec. 31, 2022
Segment and Geographic Information [Abstract]
Segment and Geographic Information	Note 12—Segment and Geographic Information The Company has one reportable segment, fluid management. At December 31, 2022 and 2021, long-lived assets were located primarily in the United States.

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-15

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-31

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-42

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 40
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-40

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//280/tableOfContent

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 26
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-26

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 34
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-34

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 41
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-41

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-21

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-21

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Property, Plant and Equipment [Abstract]

Consolidated Statements of Cash Flows (FY) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating Activities
Net loss	$ (14,525)	$ (19,554)
Adjustments to reconcile net loss to cash flows from operating activities:
Depreciation and amortization	372	488
Stock-based compensation expense, net	862	1,314
Change in fair value of warrant liability	(11,827)	0
Financing expense	9,247	0
Net realized and unrealized gains on marketable securities	124	13
Changes in operating assets and liabilities:
Accounts receivable	(656)	155
Inventory	140	(143)
Other current assets	(68)	(91)
Other assets and liabilities	(96)	186
Accounts payable and accrued expenses	1,278	(211)
Net cash used in operating activities	(15,149)	(17,843)
Investing activities:
Purchases of marketable securities	0	(18,850)
Proceeds from sales of marketable securities	14,850	3,350
Purchase of property and equipment	(122)	(219)
Net cash provided by (used in) investing activities	14,728	(15,719)
Financing activities:
Proceeds from public stock offerings, net	9,449	27,896
Proceeds from warrant exercises	0	1
Payments on finance lease liability	(26)	(26)
Net cash provided by (used in) financing activities	9,423	27,871
Effect of exchange rate changes on cash	(7)	(4)
Net increase (decrease) in cash and cash equivalents	8,995	(5,695)
Cash and cash equivalents - beginning of period	8,742	14,437
Cash and cash equivalents - end of period	17,737	8,742
Supplemental schedule of non-cash activities
Inventory transferred to property, plant and equipment	42	257
Operating right-of-use asset recorded as an operating lease liability	0	901
Supplemental cash flow information
Cash paid for income taxes	$ 9	$ 11

Property, Plant and Equipment (FY) (Tables)

12 Months Ended

Dec. 31, 2022

Property, Plant and Equipment

Property, plant and equipment were as follows:

(in thousands)	December 31, 2022	December 31, 2021
Production Equipment	$1,360	$1,321
Loaners and Demo Equipment	1,444	1,364
Computer Software and Equipment	719	714
Office Furniture & Fixtures	375	364
Leasehold Improvements	253	245
Total	4,151	4,008
Accumulated Depreciation	(3,171)	(2,820)
	$980	$1,188

Nature of Business and Significant Accounting Policies, Loss Per Share (FY) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Loss per share [Abstract]
Net deemed dividends resulting from subsequent reduction in exercise price of warrants						$ 75,000
Potential shares of common stock that are not included in the calculation of diluted net loss per share [Abstract]
Potential shares of common stock that are not included in the calculation of diluted net loss per share (in shares)			1,424,626	29,388	705,302	74,580
Reported net loss with reported net loss per share [Abstract]
Net loss	$ (3,370)	$ (3,870)	$ (14,700)	$ (12,629)	$ (14,525)	$ (19,545)
Deemed dividend to preferred shareholders (see Note 4)					0	(75)
Net loss after deemed dividend					$ (14,525)	$ (19,620)
Weighted average shares outstanding - basic (in shares)	1,864,000	105,000	1,439,000	105,000	174,000	69,000
Weighted average shares outstanding - diluted (in shares)	1,864,000	105,000	1,439,000	105,000	174,000	69,000
Basic loss per share (in dollars per share)	$ (1.81)	$ (36.72)	$ (10.21)	$ (119.85)	$ (83.55)	$ (285.36)
Diluted loss per share (in dollars per share)	$ (1.81)	$ (36.72)	$ (10.21)	$ (119.85)	$ (83.55)	$ (285.36)
Stock Options [Member]
Potential shares of common stock that are not included in the calculation of diluted net loss per share [Abstract]
Potential shares of common stock that are not included in the calculation of diluted net loss per share (in shares)			111,275	11,910	10,485	7,481
Warrants to Purchase Common Stock [Member]
Potential shares of common stock that are not included in the calculation of diluted net loss per share [Abstract]
Potential shares of common stock that are not included in the calculation of diluted net loss per share (in shares)			1,308,271	16,970	679,244	16,299
Series F Convertible Preferred Stock [Member]
Potential shares of common stock that are not included in the calculation of diluted net loss per share [Abstract]
Potential shares of common stock that are not included in the calculation of diluted net loss per share (in shares)			5,080	508	5,080	50,800
Series I Convertible Preferred Stock [Member]
Potential shares of common stock that are not included in the calculation of diluted net loss per share [Abstract]
Potential shares of common stock that are not included in the calculation of diluted net loss per share (in shares)					10,493	0

Stock-Based Compensation (FY)

9 Months Ended

12 Months Ended

Sep. 30, 2023

Dec. 31, 2022

Stock-Based Compensation

Note 4 — Stock-Based Compensation

The following table presents the classification of stock-based compensation expense recognized for the periods below:

	Three months ended September 30		Nine months ended September 30
(in thousands)	2023	2022	2023	2022
Selling, general and administrative expense	$133	$199	$484	$624
Research and development expense	2	21	29	73
Total stock-based compensation expense	$135	$220	$513	$697

The total number of stock options outstanding as of September 30, 2023 and September 30, 2022 was 111,275 and 12,003, respectively.

The weighted-average assumptions used in the Black-Scholes option-pricing model are as follows for the stock options granted during the three and nine months ended September 30, 2023 and 2022:

	Three months ended September 30		Nine months ended September 30
	2023	2022	2023	2022
Expected volatility	131.06%	132.08%	152.59%	132.48%
Expected Life of options (years)	6.25	6.25	6.19	6.15
Expected dividend yield	0%	0%	0%	0%
Risk-free interest rate	4.29%	3.02%	4.16%	2.13%

Note 5— Stock-Based Compensation

Stock Options and Restricted Stock Awards

(Dollars in thousands)	2022	2021
Selling, general and administrative	$784	$1,171
Research and development	78	143
Total	$862	$1,314

Stock Options: The following is a summary of the Plans’ stock option activity during the years ended December 31:

	2022		2021
	Options Outstanding	Weighted Average Exercise Price	Options Outstanding	Weighted Average Exercise Price
Beginning Balance	7,481	$656.05	144	$40,534.00
Granted	5,833	83.96	9,081	444.83
Exercised	—	—	—	—
Forfeited/expired	(2,829)	410.34	(1,744)	2,332.06
Outstanding at December 31	10,485	$404.08	7,481	$656.05
Vested at December 31	3,531	$727.26	409	$4,218.40

The following table provides the weighted average assumptions used in the Black-Scholes option pricing model for the years ended December 31:

	2022	2021
Expected dividend yield	0%	0%
Risk-free interest rate	2.13%	1.19%
Expected volatility	132.48%	131.03%
Expected life (in years)	6.15	6.21

Revenue Recognition (FY) (Details)	12 Months Ended
Revenue Recognition (FY) (Details)	Dec. 31, 2022	Dec. 31, 2021	Sep. 30, 2023
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Abstract]
Expected timing of satisfaction, period		1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Abstract]
Expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Abstract]
Expected timing of satisfaction, period			1 year
Sales Revenue [Member] \| Customer Concentration Risk [Member] \| ASC 606 [Member] \| Maximum [Member]
Revenue, Performance Obligation [Abstract]
Concentration risk percentage	1.00%	1.00%

Revenue Recognition (Q3)	9 Months Ended	12 Months Ended
Revenue Recognition (Q3)	Sep. 30, 2023	Dec. 31, 2022
Revenue Recognition [Abstract]
Revenue Recognition	Note 2 — Revenue Recognition Net Sales: The Company sells its products in the United States primarily through a direct salesforce. Customers who purchase the Company’s products include hospitals and clinics throughout the United States. In countries outside the United States, the Company sells its products through a limited number of specialty healthcare distributors in Austria, Brazil, Colombia, The Czech Republic, Germany, Greece, Hong Kong, India, Indonesia, Israel, Italy, Panama, Romania, Singapore, Slovakia, Spain, Switzerland, Thailand, United Arab Emirates, and the United Kingdom. These distributors resell the Company’s products to hospitals and clinics in their respective geographies. International revenue represents 5% of net sales for the three and nine months ended September 30, 2023 and 2022. Revenue from product sales is recognized when the customer or distributor obtains control of the product, which occurs at a point in time, most frequently upon shipment of the product or receipt of the product, depending on shipment terms. The Company’s standard shipping terms are FOB shipping point unless the customer requests that control and title to the inventory transfer upon delivery. Revenue is measured as the amount of consideration we expect to receive, adjusted for any applicable estimates of variable consideration and other factors affecting the transaction price, which is based on the invoiced price, in exchange for transferring products. All revenue is recognized when the Company satisfies its performance obligations under the contract. The majority of the Company’s contracts have a single performance obligation and are short term in nature. The Company has entered into extended service plans with customers whose related revenue is recognized over time. This revenue represents less than 1% of net sales for the three and nine months ended September 30, 2023 and 2022. The unfulfilled performance obligations related to these extended service plans are included in deferred revenue, which is included in other current liabilities on the consolidated balance sheets. The majority of the deferred revenue is expected to be recognized within one year. Sales taxes and value added taxes in foreign jurisdictions that are collected from customers and remitted to governmental authorities are accounted for on a net basis and therefore are excluded from net sales. Revenue includes shipment and handling fees charged to customers. Shipping and handling costs associated with outbound freight after control over a product has transferred to a customer are accounted for as a fulfillment cost and are included in cost of goods sold. Product Returns: The Company offers customers a limited right of return for its products in case of non-conformity or performance issues. The Company estimates the amount of its product sales that may be returned by its customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized. The Company currently estimates product return liabilities using available industry data and its own historical sales and returns information. The Company has not received any returns to date and believes that future returns of its products will be minimal. Therefore, revenue recognized is not currently impacted by variable consideration related to product returns.	Note 2 – Revenue Recognition Net Sales The Company sells its products in the United States primarily through a direct salesforce. Customers who purchase the Company’s products include hospitals and clinics throughout the United States. In countries outside the United States, the Company sells its products through a limited number of specialty healthcare distributors in Austria, Brazil, Colombia, the Czech Republic, Germany, Greece, Hong Kong, India, Israel, Italy, Panama. Romania, Singapore, Slovakia, Spain, Switzerland, Thailand, United Arab Emirates, and the United Kingdom. These distributors resell the Company’s products to hospitals and clinics in their respective geographies. Revenue from product sales is recognized when the customer or distributor obtains control of the product, which occurs at a point in time, most frequently upon shipment of the product or receipt of the product, depending on shipment terms. The Company’s standard shipping terms are FOB shipping point unless the customer requests that control and title to the inventory transfer upon delivery. Revenue is measured as the amount of consideration we expect to receive, adjusted for any applicable estimates of variable consideration and other factors affecting the transaction price, which is based on the invoiced price, in exchange for transferring products. All revenue is recognized when the Company satisfies its performance obligations under the contract. The majority of the Company’s contracts have a single performance obligation and are short term in nature. The Company has entered into extended service plans with customers, which are recognized over time. This revenue represents less than 1% of net sales for each of the years ended December 31, 2022 and 2021. The unfulfilled performance obligations related to these extended service plans are included in deferred revenue, which is included in other current liabilities on the consolidated balance sheets. The majority of the deferred revenue is expected to be recognized within one year. Sales taxes and value added taxes in foreign jurisdictions that are collected from customers and remitted to governmental authorities are accounted for on a net basis and therefore are excluded from net sales. Revenue includes shipment and handling fees charged to customers. Shipping and handling costs associated with outbound freight after control over a product has transferred to a customer are accounted for as a fulfillment cost and are included in cost of goods sold. Product Returns: The Company offers customers a limited right of return for its product in case of non-conformity or performance issues. The Company estimates the amount of its product sales that may be returned by its customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized. The Company currently estimates product return liabilities using available industry data and its own historical sales and returns information. The Company has not received any returns to date and believes that future returns of its products will be minimal. Therefore, revenue recognized is not currently impacted by variable consideration related to product returns.

Nature of Business, Basis of Presentation and Significant Accounting Policies [Abstract]

Nature of Business and Significant Accounting Policies (FY) (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2023

Dec. 31, 2022

Potential Shares of Common Stock not Included in Diluted Net Loss Per Share

Inventories consisted of the following:

(in thousands)	September 30, 2023	December 31, 2022
Finished Goods	$811	$993
Work in Process	170	204
Raw Materials	1,659	1,609
Inventory Reserves	(304)	(145)
Total	$2,336	$2,661

Inventories consisted of the following as of December 31:

(Dollars in thousands)	2022	2021
Finished Goods	$993	$1,527
Work in Process	204	276
Raw Materials	1,609	1,281
Inventory Reserves	(145)	(241)
Total	$2,661	$2,843

Estimated Useful Lives

Depreciation expense has been calculated using the following estimated useful lives:

Production Equipment			3-7 years
Office Furniture and Fixtures			3-5 years
Computer Software and Equipment			3-4 years
Loaners and demo equipment			1-5 years
Leasehold improvements			3-5 years

	September 30
	2023	2022
Stock options	111,275	11,910
Warrants to purchase common stock	1,308,271	16,970
Series F convertible preferred stock	5,080	508
Total	1,424,626	29,388

	December 31,
	2022	2021
Stock options	10,485	7,481
Warrants to purchase common stock	679,244	16,299
Series F convertible preferred stock	5,080	50,800
Series I convertible preferred stock	10,493	—
Total	705,302	74,580

Reconciles Reported Net Loss with Reported Net Loss Per Share

The following table reconciles reported net loss with reported net loss per share for each of the three and nine months ended September 30:

	Three months ended September 30		Nine months ended September 30
(in thousands, except per share amounts)	2023	2022	2023	2022
Net loss	$(3,370)	$(3,870)	$(14,700)	$(12,629)
Weighted average shares outstanding	1,864	105	1,439	105
Basic and diluted loss per share	$(1.81)	$(36.72)	$(10.21)	$(119.85)

The following table reconciles reported net loss with reported net loss per share for the years ended December 31:

(in thousands, except per share amounts)	2022	2021
Net loss	$(14,525)	$(19,545)
Deemed dividend to preferred stockholders (see Note 4)	—	(75)
Net loss after deemed dividend	(14,525)	(19,620)
Weighted average shares outstanding	174	69
Basic and diluted loss per share	$(83.55)	$(285.36)

Subsequent Events (FY)	9 Months Ended	12 Months Ended
Subsequent Events (FY)	Sep. 30, 2023	Dec. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	Note 10 — Subsequent Events Public Offering: On October 17, 2023, the Company closed on a public offering of 150,000 units (the “Units”), with each Unit consisting of one share of the Company’s Series J Convertible Redeemable Preferred Stock, par value $0.0001 per share, with a liquidation preference of $25.00 per share (the “Series J Convertible Preferred Stock”), and one warrant (the “October 2023 Warrants”) to purchase one-half of one (0.50) share of Series J Convertible Preferred Stock. The purchase price for one Unit was $15.00, which reflects the issuance of the Series J Convertible Preferred Stock with an original issue discount. The Series J Convertible Preferred Stock has a term of three (3) years and is convertible at the option of the holder at any time into shares of the Company’s common stock at a conversion price of $1.01. If any shares of our Series J Convertible Preferred Stock are outstanding at the end of the three-year term, then the Company will promptly redeem all of such outstanding shares of Series J Convertible Preferred Stock on a pro rata basis among all of the holders of Series J Convertible Preferred Stock commencing on the third-year anniversary of the closing date of this offering (the “Mandatory Redemption Date”) in cash, to the extent legally permissible under Delaware law, or, if redemption for cash is not legally permissible in duly authorized, validly issued, fully paid and non-assessable shares of the Company’s common stock equal in number to the quotient obtained by dividing such unpaid amount by the closing price of the Company’s common stock on the Nasdaq on the Mandatory Redemption Date. Dividends on the Series J Convertible Preferred Stock will be paid, if and when declared by the Company’s board of directors, in-kind (“PIK dividends”) in additional shares of Series J Convertible Preferred Stock based on the stated value of $25.00 per share at a dividend rate of 5.0%. The PIK dividends will be paid on a quarterly basis for three (3) years following the closing date to holders of the Series J Convertible Preferred Stock of record at the close of business on October 31, January 31, April 30, and July 31 of each year. The October 2023 Warrants have a term of three (3) years. Each October 2023 Warrant has an exercise price of $7.50 (50.0% of the public offering price per Unit) per one-half of one share (0.5) of Series J Convertible Preferred Stock and is immediately exercisable. The Company is currently evaluating the accounting treatment of the Series J Convertible Preferred Stock and the October 2023 Warrants. The gross proceeds before underwriting discounts and commissions and offering expenses, were approximately $2.25 million. The Company intends to use the net proceeds from the offering for working capital and for general corporate purposes.	Note 14—Subsequent Events On January 4, 2023, shareholder approval was secured by the Company for the issuance of the common stock warrants issued in conjunction with the Company’s October 2022 financing. During 2023, through February 24, 2023, there were 660,046 common stock warrants which had converted into 660,046 shares of common stock at a $0 exercise price with no proceeds received by the Company. At-The-Market Offering On March 3, 2023, we entered into a Sales Agreement with Ladenburg Thalmann & Co. Inc. (“Ladenburg”) to create an at-the-market offering program under which we may offer and sell shares having an aggregate offering price of up to $10.0 million. Ladenburg is entitled to a commission at a fixed commission rate equal to up to 3% of the gross proceeds.

Income Taxes, Components of Income Tax Expense (FY) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Current [Abstract]
United States and state					$ 0	$ 0
Foreign, net					(9)	(9)
Deferred [Abstract]
United States and state					0	0
Foreign					0	0
Total income tax expense	$ (2)	$ (2)	$ (6)	$ (6)	$ (9)	$ (9)

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

Nature of Business, Basis of Presentation and Significant Accounting Policies [Abstract]

Operating Leases (Q3) (Details) $ in Thousands	9 Months Ended	12 Months Ended
Operating Leases (Q3) (Details) $ in Thousands	Sep. 30, 2023 USD ($) ft² $ / ft²	Dec. 31, 2022 USD ($) ft² $ / ft²
Operating Leases [Abstract]
Area of property leased under operating lease \| ft²	23,000	23,000
Monthly rent and common area maintenance charges \| $	$ 32	$ 31
Annual base rent (per square foot)	10.5	10.5
Minimum [Member]
Operating Leases [Abstract]
Annual increase per square foot (in dollars per square foot)	0.32	0.32
Maximum [Member]
Operating Leases [Abstract]
Annual increase per square foot (in dollars per square foot)	0.34	0.34

Income Taxes, Deferred Taxes and Other Information (FY) (Details) $ in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 AUD ($)
Noncurrent [Abstract]
Accrued leave	$ 397	$ 59
Stock based compensation	360	368
Net operating loss carryforward	45,405	42,363
Other	42	131
Intangibles	1,786	723
R&D credit carryforward	531	531
Total deferred tax assets	48,521	44,175
Less: valuation allowance	(48,521)	(44,175)
Total	0	0
Operating Loss Carryforwards [Abstract]
Increase in valuation allowance	4,300	4,900
Unrecognized Tax Benefits [Abstract]
Uncertain tax positions	0	0
Penalties and Interest Accrued [Abstract]
Interest and penalties accrued on uncertain tax positions	$ 0	$ 0
Earliest Tax Year [Member]
Operating Loss Carryforwards [Abstract]
Net operating loss (NOL) carryforwards, expiration date	Dec. 31, 2024
Latest Tax Year [Member]
Operating Loss Carryforwards [Abstract]
Net operating loss (NOL) carryforwards, expiration date	Dec. 31, 2038
Federal [Member]
Operating Loss Carryforwards [Abstract]
Net operating loss (NOL) carryforwards	$ 198,100
Net operating loss (NOL) carryforwards with expiration date	120,100
Net operating loss (NOL) carryforwards with no expiration date	78,000
State [Member]
Operating Loss Carryforwards [Abstract]
Net operating loss (NOL) carryforwards	$ 53,800
Australian [Member]
Operating Loss Carryforwards [Abstract]
Net operating loss (NOL) carryforwards			$ 0

Finance Lease Liability (FY)	9 Months Ended	12 Months Ended
Finance Lease Liability (FY)	Sep. 30, 2023	Dec. 31, 2022
Finance Lease Liability [Abstract]
Finance Lease Liability	Note 8 — Finance Lease Liability In 2020, the Company entered into lease agreements to finance equipment valued at $98,000. The equipment consisted of computer hardware and audio-visual equipment and is included in Property, Plant and Equipment in the accompanying consolidated financial statements. The principal amount under the lease agreements was $93,000 at the date the lease commenced, the implied interest rate is 7.5%, and the term of the lease is 39 months.	Note 9—Finance Lease Liability In 2020, the Company entered into lease agreements to finance equipment valued at $98,000. The equipment consisted of computer hardware and audio-visual equipment and is included in Property, Plant and Equipment in the accompanying consolidated financial statements. The principal amount under the lease agreements was $93,000 at the date the lease commenced, the implied interest rate is 7.5%, and the term of the lease is 39 months.

Nature of Business and Basis of Presentation (Q3)

9 Months Ended

12 Months Ended

Sep. 30, 2023

Dec. 31, 2022

Nature of Business and Basis of Presentation

Note 1 — Nature of Business and Basis of Presentation

Nature of Business: Nuwellis, Inc. (the “Company”) is a medical technology company focused on developing, manufacturing, and commercializing the Aquadex FlexFlow® and Aquadex SmartFlow® systems (collectively, the “Aquadex System”) for ultrafiltration therapy. The Aquadex System is indicated for temporary (up to eight hours) or extended (longer than 8 hours in patients who require hospitalization) use in adult and pediatric patients weighing 20 kg. or more whose fluid overload is unresponsive to medical management, including diuretics. Nuwellis, Inc. is a Delaware corporation headquartered in Minneapolis with a wholly owned subsidiary in Ireland. The Company’s common stock began trading on the Nasdaq Capital Market in February 2012.

In August 2016, the Company acquired the business associated with the Aquadex System (the “Aquadex Business”) from a subsidiary of Baxter International, Inc. (“Baxter”), and refocused its strategy to fully devote its resources to the Aquadex Business. On April 27, 2021, the Company announced that it was changing its name from CHF Solutions, Inc. to Nuwellis, Inc. to reflect the expansion of its customer base from treating fluid imbalance resulting from congestive heart failure to also include critical care and pediatric applications.

(in thousands)	September 30, 2023	December 31, 2022
Finished Goods	$811	$993
Work in Process	170	204
Raw Materials	1,659	1,609
Inventory Reserves	(304)	(145)
Total	$2,336	$2,661

	September 30
	2023	2022
Stock options	111,275	11,910
Warrants to purchase common stock	1,308,271	16,970
Series F convertible preferred stock	5,080	508
Total	1,424,626	29,388

The following table reconciles reported net loss with reported net loss per share for each of the three and nine months ended September 30:

	Three months ended September 30		Nine months ended September 30
(in thousands, except per share amounts)	2023	2022	2023	2022
Net loss	$(3,370)	$(3,870)	$(14,700)	$(12,629)
Weighted average shares outstanding	1,864	105	1,439	105
Basic and diluted loss per share	$(1.81)	$(36.72)	$(10.21)	$(119.85)

Note 1—Nature of Business and Significant Accounting Policies

Nature of Business

Nuwellis, Inc. (the “Company”) is a medical technology company focused on developing, manufacturing and commercializing the Aquadex FlexFlow® and Aquadex SmartFlow® systems (collectively, the “Aquadex System”) for ultrafiltration therapy. The Aquadex SmartFlow® system is indicated for temporary (up to eight hours) or extended (longer than 8 hours in patients who require hospitalization) use in adult and pediatric patients weighing 20 kg or more, whose fluid overload is unresponsive to medical management, including diuretics. Nuwellis, Inc. is a Delaware corporation headquartered in Minneapolis with a wholly owned subsidiary in Ireland. The Company has been listed on Nasdaq since February 2012.

Going Concern

Basis of Presentation

Use of Estimates

Cash and Cash Equivalents

Marketable securities

Accounts Receivable

Inventories

(Dollars in thousands)	2022	2021
Finished Goods	$993	$1,527
Work in Process	204	276
Raw Materials	1,609	1,281
Inventory Reserves	(145)	(241)
Total	$2,661	$2,843

Other Current Assets

Other current assets represent prepayments and deposits made by the Company.

Property, Plant and Equipment

Production Equipment			3-7 years
Office Furniture and Fixtures			3-5 years
Computer Software and Equipment			3-4 years
Loaners and demo equipment			1-5 years
Leasehold improvements			3-5 years

Depreciation expense was $372,000 and $488,000 for the years ended December 31, 2022 and 2021, respectively.

There have been no impairment losses recognized for the years ended December 31, 2022 or 2021.

Accounts Payable and Accrued Liabilities

Accrued liabilities includes amounts accrued but not invoiced related to payments owed for licensing agreements, director fees, and others.

Revenue Recognition

Foreign Currency Translation

Stock-Based Compensation

Income Taxes

Loss per share

	December 31,
	2022	2021
Stock options	10,485	7,481
Warrants to purchase common stock	679,244	16,299
Series F convertible preferred stock	5,080	50,800
Series I convertible preferred stock	10,493	—
Total	705,302	74,580

The following table reconciles reported net loss with reported net loss per share for the years ended December 31:

(in thousands, except per share amounts)	2022	2021
Net loss	$(14,525)	$(19,545)
Deemed dividend to preferred stockholders (see Note 4)	—	(75)
Net loss after deemed dividend	(14,525)	(19,620)
Weighted average shares outstanding	174	69
Basic and diluted loss per share	$(83.55)	$(285.36)

Research and Development

Recent Accounting Pronouncements

The Company evaluates subsequent events through the date the consolidated financial statements are filed for events requiring adjustment to or disclosure in the consolidated financial statements.

Condensed Consolidated Statements of Cash Flows (Q3) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Operating Activities:
Net loss	$ (14,700)	$ (12,629)
Adjustments to reconcile net loss to cash flows used in operating activities:
Depreciation and amortization	253	301
Stock-based compensation expense, net	513	697
Change in fair value of warrant liability	755	0
Net realized gain on marketable securities	(65)	0
Changes in operating assets and liabilities:
Accounts receivable	(19)	(350)
Inventory, net	325	(113)
Other current assets	(551)	(40)
Other assets and liabilities	(16)	(142)
Accounts payable and accrued expenses	(1,678)	254
Net cash used in operating activities	(15,183)	(12,022)
Investing Activities:
Proceeds from sale of marketable securities	578	0
Additions to intangible assets	(99)	0
Purchases of property and equipment	(185)	(103)
Net cash provided by (used in) investing activities	294	(103)
Financing Activities:
Proceeds from ATM stock offerings, net	2,108	0
Payments on finance lease liability	(20)	(28)
Net cash provided by (used in) financing activities	2,088	(28)
Effect of exchange rate changes on cash	(6)	1
Net increase (decrease) in cash and cash equivalents	(12,807)	(12,152)
Cash and cash equivalents - beginning of period	17,737	8,742
Cash and cash equivalents - end of period	4,930	12,053
Supplemental cash flow information
Inventory transferred to property, plant and equipment	0	37
Non-cash impact of conversion of warrants to common stock	$ 6,868	0
As Reported [Member]
Financing Activities:
Cash and cash equivalents - beginning of period		$ 24,205

Income Taxes, Effective Income Tax Rate Reconciliation (FY) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Effective income tax rate reconciliation [Abstract]
Statutory federal income tax benefit					$ 3,048	$ 4,109
State tax benefit, net of federal taxes					783	560
Foreign tax					(1)	(1)
Nondeductible/nontaxable items					548	(220)
Other					(41)	406
Valuation allowance (increase) decrease					(4,346)	(4,863)
Total income tax expense	$ (2)	$ (2)	$ (6)	$ (6)	$ (9)	$ (9)

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

Stockholders' Equity (FY) (Details)													3 Months Ended			9 Months Ended		12 Months Ended
Stockholders' Equity (FY) (Details)	Dec. 08, 2022	Dec. 05, 2022	Oct. 18, 2022 USD ($) $ / shares shares	Sep. 17, 2021 USD ($) $ / shares shares	Mar. 19, 2021 USD ($) $ / shares shares	Aug. 21, 2020 USD ($) $ / shares shares	May 05, 2020 USD ($) $ / shares shares	Apr. 01, 2020 USD ($) shares	Mar. 23, 2020 USD ($) $ / shares shares	Jan. 28, 2020 USD ($) $ / shares shares	Mar. 12, 2019 $ / shares	Nov. 27, 2017 USD ($) $ / shares shares	Sep. 30, 2023 shares	Jun. 30, 2023 $ / shares shares	Mar. 31, 2023 shares	Sep. 30, 2023 USD ($) shares	Sep. 30, 2022 USD ($) $ / shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($) shares	Oct. 31, 2022 $ / shares	Apr. 02, 2020 $ / shares shares	Nov. 06, 2019 $ / shares	Oct. 25, 2019 $ / shares	May 30, 2019 $ / shares shares	Jul. 03, 2018 $ / shares
Class of Stock Disclosures [Abstract]
Warrants exercised to purchase common stock (in shares)																				4,552,000
Proceeds from warrant exercises \| $																		$ 0	$ 1,000	$ 4,100,000
Exercise price of warrants (in dollars per share) \| $ / shares														$ 0
Preferred stock, shares outstanding (in shares)													0			0		0	0
Gross proceeds from public stock offering \| $																$ 2,108,000	$ 0
Reverse stock split	0.01
Minimum [Member]
Class of Stock Disclosures [Abstract]
Reverse stock split		0.02
Maximum [Member]
Class of Stock Disclosures [Abstract]
Reverse stock split		0.01
January 2020 Offering [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares)										5,855,000
Exercise price of warrants (in dollars per share) \| $ / shares			$ 25						$ 900	$ 1,650							$ 250
Issuance of common stock, net (in shares)										2,015,000
Public offering price (in dollars per share) \| $ / shares										$ 1,650
Gross proceeds from public stock offering \| $										$ 9,700,000
Net proceeds from public stock offering \| $										8,600,000
Down-round protection in connection with re-pricing of warrants \| $										200,000
Beneficial conversion amount \| $										$ 1,600,000
March 2020 Offering [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares)									1,387,000
Exercise price of warrants (in dollars per share) \| $ / shares									$ 1,118
Issuance of common stock, net (in shares)									1,387,000
Public offering price (in dollars per share) \| $ / shares									$ 900
Gross proceeds from public stock offering \| $									$ 1,200,000
Net proceeds from public stock offering \| $									$ 1,000,000
Warrant expiry period																		5 years 6 months
Warrants exercisable period																		6 months
April 2020 Offering [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares)																						855,000
Exercise price of warrants (in dollars per share) \| $ / shares																						$ 1,115
Issuance of common stock, net (in shares)								1,710,000
Public offering price (in dollars per share) \| $ / shares																						$ 1,302
Gross proceeds from public stock offering \| $								$ 2,200,000
Warrant expiry period																		5 years 6 months
May 2020 Offering [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares)							600,000
Exercise price of warrants (in dollars per share) \| $ / shares							$ 1,230
Issuance of common stock, net (in shares)							1,199,000
Public offering price (in dollars per share) \| $ / shares							$ 1,418
Gross proceeds from public stock offering \| $							$ 1,700,000
Warrant expiry period																		5 years 6 months
August 2020 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares)						10,647,000
Public offering price (in dollars per share) \| $ / shares						$ 1,350
Gross proceeds from public stock offering \| $						$ 14,400,000
Net proceeds from public stock offering \| $						$ 13,000,000
Number of shares issuable on the exercise of warrants (in shares)						10,647,000
Warrant expiry period																		5 years
March 2021 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares)					37,958
Gross proceeds from public stock offering \| $					$ 20,900,000
Net proceeds from public stock offering \| $					$ 18,900,000
September 2021 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares)				40,056
Gross proceeds from public stock offering \| $				$ 10,000,000
Net proceeds from public stock offering \| $				$ 9,000,000
October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Gross proceeds from public stock offering \| $			$ 11,000,000
Net proceeds from public stock offering \| $			$ 9,400,000
Warrants to Purchase Common Stock [Member]
Class of Stock Disclosures [Abstract]
Number of warrants vested (in shares)																0		0
Warrants to Purchase Common Stock [Member] \| Consultant [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares)																									33
Exercise price of warrants (in dollars per share) \| $ / shares																									$ 9,540
Common Stock [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares)													0	657,333				209,940	78,014
Conversion of preferred stock into common stock (in shares)															10,493			221,078
Common Stock [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares)			209,940
Number of shares in one unit (in shares)			1
Series F Convertible Preferred Stock [Member]
Class of Stock Disclosures [Abstract]
Gross proceeds from issuance of convertible preferred stock \| $												$ 18,000,000
Net proceeds from issuance of convertible preferred stock \| $												$ 16,200,000
Conversion price (in dollars per share) \| $ / shares												$ 189,000														$ 89,040
Number of consecutive trading days considered for expiration																20 days		20 days
Number of consecutive trading days																30 days		30 days
Percentage of volume weighted average price of common stock												300.00%
Trading volume for each trading day \| $												$ 200,000
Preferred stock issued (in shares)												18,000	127			127		127	127
Number of shares issuable on conversion of preferred stock (in shares)												96
Preferred stock, shares outstanding (in shares)													127			127		127	127
Aggregate cash placement fee											8.00%
Series F Convertible Preferred Stock [Member] \| Minimum [Member]
Class of Stock Disclosures [Abstract]
Percentage of volume weighted average price of common stock												300.00%
Trading volume for each trading day \| $												$ 200,000
Series F Convertible Preferred Stock [Member] \| March 2019 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares											$ 15,750
Series F Convertible Preferred Stock [Member] \| October 2019 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares																								$ 4,230
Series F Convertible Preferred Stock [Member] \| November 2019 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares																							$ 2,983
Series F Convertible Preferred Stock [Member] \| January 2020 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares										$ 1,650
Exercise price of warrants (in dollars per share) \| $ / shares										900
Series F Convertible Preferred Stock [Member] \| March 2020 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares									$ 900
Series F Convertible Preferred Stock [Member] \| March 2021 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares					$ 550
Exercise price of warrants (in dollars per share) \| $ / shares					$ 550
Series F Convertible Preferred Stock [Member] \| September 2021 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares				$ 250
Exercise price of warrants (in dollars per share) \| $ / shares				$ 250
Series F Convertible Preferred Stock [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares			$ 25														$ 250				$ 25
Series F Convertible Preferred Stock [Member] \| Warrants to Purchase Common Stock [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares)												191
Series F Convertible Preferred Stock [Member] \| Warrant Series 1 [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares)												16
Exercise price of warrants (in dollars per share) \| $ / shares												$ 189,000
Series F Convertible Preferred Stock [Member] \| Warrant Series 2 [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares)												4
Exercise price of warrants (in dollars per share) \| $ / shares												$ 189,000
Series H Preferred Stock [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share) \| $ / shares										$ 1,650
Preferred stock, shares outstanding (in shares)																				0
Maximum percentage of the applicable Unit offering price, by which exercise price can be lower than adjustment										10.00%
Conversion of preferred stock into common stock (in shares)																				115,173
Series H Preferred Stock [Member] \| January 2020 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares)										115,173,000
Series I Preferred Stock [Member]
Class of Stock Disclosures [Abstract]
Preferred stock issued (in shares)													0			0		1,049,280	0
Preferred stock, shares outstanding (in shares)													0			0		1,049,280	0
Series I Preferred Stock [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares)			23,157,124
Number of shares in one unit (in shares)			1
Class A Unit [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares)			209,940
Common stock offering price per share (in dollars per share) \| $ / shares			$ 25
Number of shares in one unit (in shares)			1
Common stock exercise price per share (in dollars per share) \| $ / shares			$ 25
Class A Unit [Member] \| Warrants [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Number of shares in one unit (in shares)			1.5
Class B Unit [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares)			23,157,124
Common stock offering price per share (in dollars per share) \| $ / shares			$ 0.25
Common stock exercise price per share (in dollars per share) \| $ / shares			$ 0
Class B Unit [Member] \| Warrants [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Number of shares in one unit (in shares)			1.5

Stockholders' Equity (FY)	9 Months Ended	12 Months Ended
Stockholders' Equity (FY)	Sep. 30, 2023	Dec. 31, 2022
Stockholders' Equity [Abstract]
Stockholders' Equity	Note 3 — Stockholders’ Equity Series F Convertible Preferred Stock: On November 27, 2017, the Company closed on an underwritten public offering of Series F convertible preferred stock and warrants to purchase shares of common stock for gross proceeds of $18.0 million. Net proceeds totaled approximately $16.2 million after deducting the underwriting discounts and commissions and other costs associated with the offering. The offering was comprised of Series F convertible preferred stock, convertible into shares of the Company’s common stock at a conversion price of $189,000 per share. Each share of Series F convertible preferred stock was accompanied by a Series 1 warrant, which expired on the first anniversary of its issuance, to purchase 16 shares of the Company’s common stock at an exercise price of $189,000 per share, and a Series 2 warrant, which expires on the seventh anniversary of its issuance, to purchase 4 shares of the Company’s common stock at an exercise price of $189,000 per share. The Series F convertible preferred stock has full ratchet price-based anti-dilution protection, subject to customary carve-outs, in the event of a down-round financing at a price per share below the conversion price of the Series F convertible preferred stock (which protection will expire if, during any 20 of 30 consecutive trading days, the volume weighted average price of the Company’s common stock exceeds 300% of the then-effective conversion price of the Series F convertible preferred stock and the daily dollar trading volume for each trading day during such period exceeds $200,000). The exercise price of the warrants is fixed and does not contain any variable pricing features, nor any price-based anti-dilutive features, apart from customary adjustments for stock splits, combinations, reclassifications, stock dividends or fundamental transactions. A total of 18,000 shares of Series F convertible preferred stock convertible into 96 shares of common stock and warrants to purchase 191 shares of common stock were issued in the offering. Effective March 12, 2019, the conversion price of the Series F convertible preferred stock was reduced from $89,040 to $15,750, the per share price to the public of the Series G convertible preferred stock issued in the March 2019 Offering. Effective October 25, 2019, the conversion price of the Series F convertible preferred stock was reduced from $15,750 to $4,230, and on November 6, 2019, from $4,230 to $2,983, the per share price to the public in the October and November 2019 transactions, respectively. Effective January 28, 2020, the conversion price of the Series F convertible preferred stock was reduced from $2,983 to $1,650, the per share price to the public of the Series H convertible preferred stock which closed in an underwritten public offering on January 28, 2020. Effective March 23, 2020, the conversion price of the Series F convertible preferred stock was reduced from $1,650 to $900, the per share price to the public in the March 2020 transaction. In connection with the March 2021 Offering, the conversion price of the Series F convertible preferred stock was reduced from $900 to $550, the per share price to the public in the March 2021 Offering. In addition, the exercise price of the common stock warrants issued in connection with the offering consummated by the Company on January 28, 2020 (the “January 2020 Offering”) was reduced from $900 to $550, the per share price to the public in the March 2021 Offering. In connection with the September 2021 offering, the conversion price of the Series F convertible preferred stock was reduced from $550 to $250, the per share price to the public in the September 2021 offering, described below. In connection with the October 2022 offering, the conversion price of the Series F convertible preferred stock was reduced from $250 to $25, the per share price to the public in the October 2022 offering, described below. As of September 30, 2023, and December 31, 2022, 127 shares of the Series F convertible preferred stock remained outstanding. March 2021 Offering: On March 19, 2021, the Company closed on an underwritten public offering of 37,958 shares of common stock, for gross proceeds of approximately $20.9 million (the “March 2021 Offering”). Net proceeds totaled approximately $18.9 million after deducting the underwriting discounts and commissions and other costs associated with the offering and after giving effect to the underwriters’ full exercise of their overallotment option. September 2021 Offering: On September 17, 2021, the Company closed on an underwritten public offering of 40,056 shares of common stock, for gross proceeds of approximately $10.0 million (the “September 2021 Offering”). Net proceeds totaled approximately $9.0 million after deducting the underwriting discounts and commissions and other costs associated with the offering and after giving effect to the underwriters’ full exercise of their overallotment option. In connection with the September 2021 Offering, the conversion price of the Series F convertible preferred stock was reduced from $550 to $250, the per share price to the public in the September 2021 Offering. In addition, the exercise price of the common stock warrants issued in connection with the January 2020 Offering was reduced from $550 to $250, the per share price to the public in the September 2021 Offering. October 2022 Offering: On October 18, 2022, the Company closed on an underwritten public offering of 209,940 shares of common stock and 23,157,124 shares of Series I convertible preferred stock, for gross proceeds of approximately $11.0 million (the “October 2022 Offering”). Net proceeds totaled approximately $9.4 million after deducting underwriting discounts and commissions and other costs associated with the offering and after giving effect to the underwriters’ full exercise of their overallotment option. The offering was comprised of (1) 209,940 Class A Units, priced at a public offering price of $25 per Class A Unit, with each Class A Unit consisting of one share of common stock and 1.5 warrants to purchase one share of common stock at an exercise price of $25 per share, and (2) 23,157,124 Class B Units, priced at a public offering price of $0.25 per Class B Unit, with each Class B Unit consisting of one share of Series I convertible preferred stock, convertible into one share of common stock for every one hundred shares of Series I convertible preferred stock, and 1.5 warrants to purchase one share of common stock for every one hundred shares of Series I convertible preferred stock. The warrants included a cashless exercise provision that upon becoming exercisable, the warrant holders could exercise the warrants for common stock at a zero-dollar exercise price. The warrants became exercisable beginning on the effective date of a reverse stock split in an amount sufficient to permit the exercise in full of the warrants, contingent upon stockholder approval of (i) such reverse stock split and (ii) of the exercisability of the warrants under Nasdaq rules, and they expire on the sixth anniversary of the initial exercise date. On December 8, 2022, following a special meeting of stockholders, the Company’s board of directors approved a one-for-one hundred reverse stock split of the Company’s issued and outstanding shares of common stock (the “Reverse Stock Split”). On December 9, 2022, the Company filed with the Secretary of State of the State of Delaware a Certificate of Amendment to its Certificate of Incorporation to effect the Reverse Stock Split. The Reverse Stock Split became effective as of 5:00 p.m. Eastern Time on December 9, 2022, and the Company’s common stock began trading on a split-adjusted basis when the market opened on December 12, 2022. The conversion price of the preferred stock issued in the October 2022 offering was fixed and does not contain any variable pricing feature or any price-based anti-dilutive feature. The preferred stock issued in this transaction includes a beneficial ownership blocker but has no dividend rights (except to the extent that dividends are also paid on the common stock) or liquidation preference and, subject to limited exceptions, has no voting rights. The securities comprising the units are immediately separable and were issued separately. This reverse stock split did not change the par value of the Company’s common stock or the number of common or preferred shares authorized by the Company’s Fourth Amended and Restated Certificate of Incorporation, as amended. All share and per-share amounts in this quarterly report have been retroactively adjusted to reflect the reverse stock splits for all periods presented. On January 4, 2023, the Company secured stockholder approval for the exercisability of the common stock warrants issued in the October 2022 Offering. The warrants were subsequently determined to be equity-classified warrants and were marked to market, then reclassified to the equity section of the consolidated balance sheet. Through June 30, 2023, 660,046 common stock warrants had converted into 660,046 shares of common stock at a zero-dollar exercise price, with no proceeds received by the Company. In connection with the October 2022 Offering, the conversion price of the Series F convertible preferred stock was reduced from $250 to $25, the per share price to the public in the October 2022 Offering. In addition, the exercise price of the common stock warrants issued in connection with the January 2020 Offering was reduced from $250 to $25, the per share price to the public in the October 2022 Offering. 2023 At-the-Market Program: In March 2023, the Company filed a Prospectus Supplement to its Registration Statement on Form S-3 with the SEC in connection with a proposed At-the-Market Securities offering (the “At-the-Market Program”). During the three months and nine months ended September 30, 2023, the Company issued none and 657,333 shares of common stock under the At-the-Market Program for gross proceeds of none and approximately $2.3 million, respectively. Net proceeds for the three and nine months ended September 30, 2023, totaled none approximately $2.1 million, respectively, after deducting the underwriting discounts and commissions and other costs associated with the offering. Underwriter and Placement Agent Fees: In connection with the offerings described above, the Company paid the underwriter or placement agent, as applicable, an aggregate cash fee equal to 8% of the aggregate gross proceeds raised in each of the offerings, except with respect to the issuances made pursuant to the At-the-Market Program, for which the placement fee was equal to 3% of the aggregate gross proceeds. Market-Based Warrants: On May 30, 2019, the Company granted a market-based warrant to a consultant in exchange for investor relations services. The warrant represents the right to acquire up to 33 shares of the Company’s common stock at an exercise price of $9,540 per share, based on the closing stock price of the Company’s common shares on May 30, 2019. The warrant is subject to a vesting schedule based on the Company achieving certain market stock prices within a specified period of time. The warrant expires on May 30, 2024 and had not vested as of September 30, 2023. Supply Agreement Warrants: On June 19, 2023, we entered into a Supply and Collaboration Agreement (the “Supply Agreement”) with DaVita Inc., a Delaware corporation (“DaVita”), pursuant to which DaVita will pilot the Aquadex ultrafiltration therapy system to treat adult patients with congestive heart failure and related conditions within select U.S. markets. The pilot program is expected to launch by the end of fourth quarter 2023 and extend through May 31, 2024 (the “Pilot”). Through the Pilot, ultrafiltration therapy using Aquadex will be offered at a combination of DaVita’s hospital customer and outpatient center locations, with both companies collaborating on the roll-out of the therapy, clinician training, and patient support. At the conclusion of the Pilot, DaVita has the option, in its sole discretion, to extend the Supply Agreement with the Company for continued provision of both inpatient and outpatient ultrafiltration services for up to 10 years (“Ultrafiltration Services Approval”). In conjunction with the Supply Agreement, the Company issued DaVita a warrant to purchase up to an aggregate of 1,289,081 shares of common stock of the Company, par value $0.0001 per share, at an exercise price of $3.2996 per share (the “DaVita Warrant”), provided that at no time can the DaVita Warrant be exercised for an amount of shares that would represent greater than 19.9% ownership in the Company subject to certain vesting milestones. The DaVita Warrant is expected to vest in four tranches as follows: (i) 25% upon receipt of notice to extend the Supply Agreement past the initial pilot-term; (ii) 25% upon the attainment by the Company of a net revenue achievement from DaVita’s efforts pursuant to the Supply Agreement within twelve months of Ultrafiltration Services Approval; (iii) 25% upon the attainment by the Company of a net revenue achievement from DaVita’s efforts pursuant to the Supply Agreement within twenty-four months of Ultrafiltration Services Approval; and (iv) 25% upon the attainment by the Company of a net revenue achievement from DaVita’s efforts pursuant to the Supply Agreement within thirty-six months of Ultrafiltration Services Approval. This warrant had not vested as of September 30, 2023. The Company evaluated the accounting treatment for the DaVita Warrant pursuant to ASC 718, “Stock Compensation,” and ASC 480, “Distinguishing Liabilities from Equity,” and concluded that the DaVita Warrant should be classified as an equity instrument on the balance sheet as of September 30, 2023. In accordance with this treatment, the Company’s management concluded none of the performance-based vesting conditions of the DaVita warrant were probable of vesting as of September 30, 2023, and therefore, no expense associated with the DaVita Warrant was recognized in the Company’s financial statements as of that date. The Company will continue to evaluate the probability of achieving the performance milestones associated with the DaVita Supply Agreement and will record the related equity-based expense in its financial statements based on the grant date fair value of the DaVita Warrant when management deems it is probable that the performance-based vesting conditions will be achieved.	Note 4—Stockholders’ Equity Series F Convertible Preferred Stock: On November 27, 2017, the Company closed on an underwritten public offering Series F Convertible Preferred Stock and warrants to purchase shares of common stock for gross proceeds of $18.0 million. Net proceeds totaled approximately $16.2 million after deducting the underwriting discounts and commissions and other costs associated with the offering. The offering was comprised of Series F convertible preferred stock, convertible into shares of the Company’s common stock at a conversion price of $189,000 per share. Each share of Series F convertible preferred stock was accompanied by a Series 1 warrant, which was to expire on the first anniversary of its issuance, to purchase 16 shares of the Company’s common stock at an exercise price of $189,000 per share, and a Series 2 warrant, which expires on the seventh anniversary of its issuance, to purchase 4 shares of the Company’s common stock at an exercise price of $189,000 per share. The Series F convertible preferred stock has full ratchet price-based anti-dilution protection, subject to customary carve-outs, in the event of a down-round financing at a price per share below the conversion price of the Series F convertible preferred stock (which protection will expire if, during any 20 of 30 consecutive trading days, the volume weighted average price of the Company’s common stock exceeds 300% of the then-effective conversion price of the Series F convertible preferred stock and the daily dollar trading volume for each trading day during such period exceeds $200,000). The exercise price of the warrants is fixed and does not contain any variable pricing features, nor any price based anti-dilutive features, apart from customary adjustments for stock splits, combinations, reclassifications, stock dividends or fundamental transactions. A total of 18,000 shares of Series F convertible preferred stock convertible into 96 shares of common stock and warrants to purchase 191 shares of common stock were issued in the offering. Effective March 12, 2019, the conversion price of the Series F convertible preferred stock was reduced from $89,040 to $15,750, the per share price to the public of the Series G convertible preferred stock issued in the March 2019 Offering. Effective October 25, 2019, the conversion price of the Series F convertible preferred stock was reduced from $15,750 to $4,230, and on November 6, 2019, from $4,230 to $2,983, the per share price to the public in the October and November 2019 transactions, respectively. Effective January 28, 2020, the conversion price of the Series F convertible preferred stock was reduced from $2,983 to $1,650, the per share price to the public of the Series H convertible preferred stock which closed in an underwritten public offering on January 28, 2020, described below. Effective March 23, 2020, the conversion price of the Series F convertible preferred stock was reduced from $1,650 to $900, the per share price to the public in the March 2020 transaction, described below. In connection with the September 2021 offering, the conversion price of the Series F convertible preferred stock was reduced from $550 to $250, the per share price to the public in the September 2021 offering, described below. In connection with the October 2022 offering, the conversion price of the Series F convertible preferred stock was reduced from $250 to $25, the per share price to the public in the October 2020 offering, described below. As of December 31, 2022, and December 31, 2021, 127 shares of the Series F convertible preferred stock remained outstanding. Series H Convertible Preferred Stock and January 2020 Offering: On January 28, 2020, the Company closed on an underwritten public offering of common stock, Series H convertible preferred stock, and warrants to purchase shares of common stock for gross proceeds of $9.7 million, which included the full exercise of the underwriter’s over-allotment option to purchase additional shares and warrants (“January 2020 Offering”). Net proceeds totaled approximately $8.6 million after deducting the underwriting discounts and commissions and other costs associated with the offering. The Series H convertible preferred stock included a beneficial conversion amount of $1.6 million, representing the intrinsic value of the shares at the time of issuance, and $0.2 million of down-round protection in connection with the re-pricing of the warrants following the March 2020 offering described below. This amount is reflected as an increase to the loss per share allocable to common stockholders in the year ended December 31, 2020. The January 2020 Offering was comprised of 2,015 shares of common stock priced at $1,650 per share and 115,173 shares of Series H convertible preferred stock, convertible into common stock at $1,650 per share, including the full exercise of the over-allotment option. Each share of Series H convertible preferred stock and each share of common stock was accompanied by a warrant to purchase common stock. The warrants are exercisable into 5,855 shares of common stock. The conversion price of the preferred stock issued in the transaction is fixed and does not contain any variable pricing feature or any price-based anti-dilutive feature. The preferred stock issued in this transaction includes a beneficial ownership blocker but has no dividend rights (except to the extent that dividends are also paid on the common stock) or liquidation preference, and, subject to limited exceptions, has no voting rights. The securities comprising the units are immediately separable and were issued separately. The warrants were exercisable beginning on the closing date and expire on the fifth anniversary of the closing date and had an initial exercise price per share equal to $1,650 per share, subject to appropriate adjustment in the event of subsequent equity sales of common stock or securities convertible into common stock for an exercise price per share less than the exercise price per share of the warrants then in effect (but in no event lower than 10% of the applicable unit offering price), or in the event of recapitalization events, stock dividends, stock splits, stock combinations, reclassifications, reorganizations or similar events affecting our common stock. Effective March 23, 2020, the exercise price of these warrants was reduced from $1,650 to $900, the per share price to the public in the March 2020 offering, described below. As of December 31, 2020, all 115,173 shares of the Series H convertible preferred stock had been converted into common stock and none remained outstanding. As of December 31, 2020, warrants to purchase 4,552 shares of common stock had been exercised for total cash proceeds of $4.1 million. March 2020 Offering: On March 23, 2020, the Company closed on a registered direct offering of 1,387 shares of its common stock at a price to the public of $900 per share, for gross proceeds of approximately $1.2 million, or $1.0 million net proceeds, after deducting commissions and offering expenses. In a concurrent private placement, the Company agreed to issue to the investors in the registered direct offering warrants to purchase up to 1,387 shares of the Company’s common stock. The warrants to purchase up to 1,387 shares of common stock have an exercise price of $1,118 per share, were exercisable six months from the date of issuance, and will expire five and a half years from the date of issuance. April 2020 Offering: On April 1, 2020, the Company closed on a registered direct offering of 1,710 shares of its common stock at a price to the public of $1,302 per share, for gross proceeds of approximately $2.2 million, prior to deduction of commissions and offering expenses related to the transaction. In a concurrent private placement, the Company agreed to issue to the investors in the registered direct offering warrants to purchase up to 855 shares of the Company’s common stock. The warrants have an exercise price of $1,115 per share, were exercisable immediately, and will expire five and a half years from the date of issuance. May 2020 Offering: On May 5, 2020, the Company closed on a registered direct offering of 1,199 shares of its common stock at a price to the public of $1,418 per share, for gross proceeds of approximately $1.7 million, prior to deduction of commissions and offering expenses related to the transaction. In a concurrent private placement, the Company agreed to issue to the investors in the registered direct offering warrants to purchase up to 600 shares of the Company’s common stock. The warrants have an exercise price of $1,230 per share, were exercisable immediately, and will expire five and a half years from the date of issuance. August 2020 Offering: On August 21, 2020, the Company closed on an underwritten public offering of common stock and warrants to purchase shares of common stock for gross proceeds of approximately $14.4 million, which included the full exercise of the underwriter’s over-allotment option to purchase additional shares and warrants (“August 2020 Offering”). Net proceeds totaled approximately $13.0 million after deducting the underwriting discounts and commissions and other costs associated with the offering. The August 2020 Offering was comprised of 10,647 shares of common stock priced at $1,350 per share. Each share of common stock was accompanied by a warrant to purchase common stock. The warrants are exercisable into 10,647 shares of common stock. The securities comprising the units are immediately separable and were issued separately. The warrants were exercisable beginning on the effective date of our stockholders’ approval of a reverse stock split in an amount sufficient to permit the exercise in full of the warrants, which occurred on October 6, 2020, and will expire on the five-year anniversary of the closing date. March 2021 Offering: On March 19, 2021, the Company closed on an underwritten public offering of 37,958 shares of common stock, for gross proceeds of approximately $20.9 million (the “March 2021 Offering”). Net proceeds totaled approximately $18.9 million after deducting the underwriting discounts and commissions and other costs associated with the offering and after giving effect to the underwriters’ full exercise of their overallotment option. In connection with the March 2021 Offering, the conversion price of the Series F convertible preferred stock was reduced from $900 to $550, the per share price to the public in the March 2021 Offering. In addition, the exercise price of the common stock warrants issued in connection with the January 2020 Offering was reduced from $900 to $550, the per share price to the public in the March 2021 Offering. September 2021 Offering: On September 17, 2021, the Company closed on an underwritten public offering of 40,056 shares of common stock, for gross proceeds of approximately $10.0 million (the “September 2021 Offering”). Net proceeds totaled approximately $9.0 million after deducting the underwriting discounts and commissions and other costs associated with the offering and after giving effect to the underwriters’ full exercise of their overallotment option. In connection with the September 2021 Offering, the conversion price of the Series F convertible preferred stock was reduced from $550 to $250, the per share price to the public in the September 2021 Offering. In addition, the exercise price of the common stock warrants issued in connection with the January 2020 Offering was reduced from $550 to $250, the per share price to the public in the September 2021 Offering. October 2022 Offering: On October 18, 2022, the Company closed on an underwritten public offering of 209,940 shares of common stock and 23,157,124 shares of Series I convertible preferred stock, for gross proceeds of approximately $11.0 million (the “October 2022 Offering”). Net proceeds totaled approximately $9.4 million after deducting underwriting discounts and commissions and other costs associated with the offering and after giving effect to the underwriters’ full exercise of their overallotment option. The offering was comprised of (1) 209,940 Class A Units, priced at a public offering price of $25 per Class A Unit, with each Class A Unit consisting of one share of common stock for every one hundred shares of Series I convertible preferred stock and 1.5 warrants to purchase one share of common stock at an exercise price of $25 per share, and (2) 23,157,124 Class B Units, priced at a public offering price of $0.25 per Class B Unit, with each Class B Unit consisting of one share of Series I convertible preferred stock, convertible into one share of common stock for every one hundred shares of Series I convertible preferred stock, and 1.5 warrants to purchase one share of common stock for every one hundred shares of Series I convertible preferred stock. The warrants included a cashless exercise provision that upon becoming exercisable, the warrant holders could exercise at a $0.00 exercise price. The warrants became exercisable beginning on the effective date of a reverse stock split in an amount sufficient to permit the exercise in full of the warrants, contingent upon stockholder approval of such reverse stock split and of the exercisability of the warrants under Nasdaq rules, and will expire on the sixth anniversary of the initial exercise date. On December 8, 2022, following a special meeting of stockholders, the Company’s board of directors approved a one-for-one hundred reverse stock split of the Company’s issued and outstanding shares of common stock (the “Reverse Stock Split”). On December 9, 2022, the Company filed with the Secretary of State of the State of Delaware a Certificate of Amendment to its Certificate of Incorporation (the “Certificate of Amendment”) to effect the Reverse Stock Split. The Reverse Stock Split became effective as of 5:00 p.m. Eastern Time on December 9, 2022, and the Company’s common stock began trading on a split-adjusted basis when the market opened on December 12, 2022. The conversion price of the preferred stock issued in the transaction was fixed and does not contain any variable pricing feature or any price-based anti-dilutive feature. The preferred stock issued in this transaction includes a beneficial ownership blocker but has no dividend rights (except to the extent that dividends are also paid on the common stock) or liquidation preference and, subject to limited exceptions, has no voting rights. The securities comprising the units are immediately separable and were issued separately. In connection with the October 2022 Offering, the conversion price of the Series F convertible preferred stock was reduced from $250 to $25, the per share price to the public in the October 2022 Offering. In addition, the exercise price of the common stock warrants issued in connection with the January 2020 Offering was reduced from $250 to $25, the per share price to the public in the October 2022 Offering. Placement Agent Fees: In connection with the offerings described above, the Company paid the placement agents an aggregate cash placement fee equal to 8% of the aggregate gross proceeds raised in each of the offerings. Market-Based Warrants: On May 30, 2019, the Company granted a market-based warrant to a consultant in exchange for investor relations services. The warrant represents the right to acquire up to 33 shares of the Company’s common stock at an exercise price of $9,540 per share, the closing stock price of the Company’s common shares on May 30, 2019. The warrant is subject to a vesting schedule based on the Company achieving certain market stock prices within a specified period of time. The warrant expires on May 30, 2024. None of these warrants had vested as of December 31, 2022. Reverse Stock Split: On December 5, 2022, the Company’s stockholders approved the Company’s management to execute a reverse split of its outstanding common stock at a ratio in the range of 1-for-50 to 1-for-100 and, on December 8, 2022, the Company’s board of directors approved a 1-for-100 reverse split of the Company’s outstanding common stock that became effective after trading on December 9, 2022. This reverse stock split did not change the par value of the Company’s common stock or the number of common or preferred shares authorized by the Company’s Fourth Amended and Restated Certificate of Incorporation, as amended. All share and per-share amounts have been retroactively adjusted to reflect the reverse stock splits for all periods presented.

The entire disclosure for equity.