0001140361-24-024996 | 10-Q | XBRL Viewer

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	39,352,000	39,352,000
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	6,801,443	5,682,461
Common stock, shares outstanding (in shares)	6,801,443	5,682,461
Series J Convertible Preferred Stock [Member]
Mezzanine Equity
Mezzanine equity, par value (in dollars per share)	$ 0.0001	$ 0.0001
Mezzanine equity, shares authorized (in shares)	600,000	600,000
Mezzanine equity, shares issued (in shares)	82	11,950
Mezzanine equity, shares outstanding (in shares)	82	11,950
Series A Junior Participating Preferred Stock [Member]
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	30,000	30,000
Preferred stock, shares outstanding (in shares)	0	0
Series F Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	18,000	18,000
Preferred stock, shares issued (in shares)	127	127
Preferred stock, shares outstanding (in shares)	127	127

Commitments and Contingencies	3 Months Ended
Commitments and Contingencies	Mar. 31, 2024
Commitments and Contingencies [Abstract]
Commitments and Contingencies	Note 8—Commitments and Contingencies Employee Retirement Plan: The Company has a 401(k) retirement plan that provides retirement benefits to all eligible 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, is 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 on the later to occur of 30 days after achievement of the milestone event or April 1, 2024. As of December 31, 2023, the Company concluded it was probable HDE approval would be obtained and recorded a liability of $450,000 on the consolidated balance sheet. On February 22, 2024, SeaStar obtained HDE approval. As of March 31, 2024, the milestone payment has not been paid.

Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2024

Stock-Based Compensation [Abstract]

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 March 31
(in thousands)	2024		2023
Selling, general and administrative expense	$	157	$	172
Research and development expense		1		9
Total stock-based compensation expense	$	158	$	181

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 months ended March 31, 2024 and 2023:

	Three months ended March 31
	2024			2023
Expected volatility		138.71	%		159.32	%
Expected Life of options (years)		5.51			6.25
Expected dividend yield		0	%		0	%
Risk-free interest rate		3.94	%		4.18	%

Commitments and Contingencies (Details) - SeaStar Medical Holding Corporation [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Dec. 27, 2022
Commitments and Contingencies [Abstract]
Milestone payment due		$ 450
Payment period after achievement of milestone event	30 days
Milestone payment made	$ 0

Nature of Business and Basis of Presentation (Tables)

3 Months Ended

Mar. 31, 2024

Nature of Business and Basis of Presentation [Abstract]

Inventories

Inventories consisted of the following:

(in thousands)	March 31, 2024			December 31, 2023
Finished Goods	$	651		$	393
Work in Process		198			207
Raw Materials		1,342			1,472
Inventory Reserves		(60	)		(75	)
Total	$	2,131		$	1,997

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

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:

	March 31
	2024		2023

Stock options		147,316		105,296
Warrants to purchase common stock		2,137,323		19,190
Series F convertible preferred stock		125,857		5,080
Series J convertible preferred stock		2,030		—
Total		2,412,526		129,566

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 months ended March 31:

	Three months ended March 31
	2024			2023
(in thousands, except per share amounts)
Net loss	$	(4,330	)	$	(6,485	)
Deemed dividend attributable to Series J Convertible Preferred Stock		541			—
Net loss after deemed dividend		(3,789	)		(6,485	)
Weighted average shares outstanding		6,286			1,126
Basic and diluted loss per share	$	(0.60	)	$	(5.76	)

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Condensed Consolidated Statements of Operations and Comprehensive Loss [Abstract]
Net sales	$ 1,857	$ 1,826
Cost of goods sold	666	759
Gross profit	1,191	1,067
Operating expenses:
Selling, general and administrative	4,606	5,490
Research and development	1,334	1,428
Total operating expenses	5,940	6,918
Loss from operations	(4,749)	(5,851)
Other income (expense), net	(101)	123
Change in fair value of warrant liability	522	(755)
Loss before income taxes	(4,328)	(6,483)
Income tax expense	(2)	(2)
Net loss	(4,330)	(6,485)
Deemed dividend attributable to Series J Convertible Preferred Stock	541	0
Net loss attributable to common stockholders	$ (3,789)	$ (6,485)
Basic loss per share (in dollars per share)	$ (0.6)	$ (5.76)
Diluted loss per share (in dollars per share)	$ (0.6)	$ (5.76)
Weighted average shares outstanding - basic (in shares)	6,286,298	1,125,993
Weighted average shares outstanding - diluted (in shares)	6,286,298	1,125,993
Other comprehensive loss:
Net loss	$ (4,330)	$ (6,485)
Unrealized gain on marketable securities	0	6
Foreign currency translation adjustments	(9)	(7)
Total comprehensive loss	$ (4,339)	$ (6,486)

Subsequent Events	3 Months Ended
Subsequent Events	Mar. 31, 2024
Subsequent Events [Abstract]
Subsequent Events	Note 9- Subsequent Events Public Offering: On April 30, Nuwellis closed on an underwritten public offering of 11,250,000 shares of its common stock (or pre-funded warrants in lieu thereof) and warrants to purchase up to an aggregate of 16,875,000 shares of its common stock at a combined public offering price $0.24 per share (or pre-funded warrant in lieu thereof) and associated warrant. Each share of common stock (or prefunded warrant in lieu thereof) was sold together with one warrant to purchase one and a half shares of common stock. The warrants have an exercise price of $0.40 per share, are exercisable immediately upon issuance, and will expire five years following the date of issuance. Each whole common warrant entitles the holder thereof to purchase one share of common stock. The common warrants contain a reset of the exercise price, effective upon the Warrant Stockholder Approval, to a price equal to the lesser of (i) the then exercise price, (ii) the lowest volume weighted average price for the five trading days immediately following the date we effect a reverse stock split in the future and (iii) if we effect a reverse stock split prior to obtaining the Warrant Stockholder Approval, the lowest volume weighted average price for the five trading days immediately following the date we obtain the Warrant Stockholder Approval. Upon such a reset, there will be a proportionate adjustment to the number of shares underlying the common warrants. In addition, the common warrants will provide for, effective upon the Warrant Stockholder Approval, full ratchet anti-dilution adjustment to the exercise price and number of shares underlying the common warrants upon our issuance of our common stock or common stock equivalents at a price per share that is less than the exercise price of the common warrants, subject to certain exemptions. In no event will the exercise price of the common warrants with respect to either adjustment be reduced below a floor price of $0.06. The gross proceeds to Nuwellis from the offering, before deducting the placement agent fees and other offering expenses were approximately $2.7 million. Net proceeds totaled approximately $2.1 million after deducting the underwriting discounts and commissions and other costs associated with the offering.

Nature of Business and Basis of Presentation

3 Months Ended

Mar. 31, 2024

Nature of Business and Basis of Presentation [Abstract]

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.

Principles of Consolidation: The accompanying condensed consolidated balance sheet as of December 31, 2023, 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, 2023.

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, 2023 and 2022 and through March 31, 2024, 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 March 31, 2024, the Company had an accumulated deficit of $292.0 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 from the date of this Form 10-Q filing.

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 its sales and marketing capabilities, product development, purchasing inventory, manufacturing components, generating additional clinical evidence supporting the efficacy of the Aquadex System, 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 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.

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. In 2023, the Company issued shares under the at-the-market program for aggregate net proceeds of approximately $2.1 million after deducting the underwriting discounts and commissions and other costs associated with the offering.

On October 12, 2023, the Company entered into a Placement Agency Agreement (the “Placement Agency Agreement”) with Lake Street Capital Markets, LLC and Maxim Group LLC, pursuant to which the Company issued and sold, in a best efforts registered public offering by the Company (the “October 2023 Offering”), 150,000 units, with each Unit consisting of (A) one share of the Company’s Series J Convertible Redeemable Preferred Stock, par value $0.0001 per share, and (B) one warrant to purchase one-half of one (0.50) share of Series J Convertible Preferred Stock, at a price to the public of $15.00 per Unit, less placement agent fees and commissions. The public offering price of $15.00 per Unit reflects the issuance of the Series J Convertible Preferred Stock with an original issue discount of 40%. The Company also registered under the Registration Statement (as defined below) an additional 362,933 shares of Series J Convertible Preferred Stock that will be issued, if and when the Company’s board of directors declares such dividends, as paid in-kind dividends and the shares of the Company’s common stock issuable upon conversion of the Series J Convertible Preferred Stock issued as PIK dividends.

The Units, the shares of Series J Convertible Preferred Stock, the Warrants, the PIK Dividend Shares, the PIK Conversion Shares as well as the shares of Series J Convertible Preferred Stock issuable upon exercise of the Warrants and the shares of the Company’s common stock, par value $0.0001 per share, issuable upon conversion of the Series J Convertible Preferred Stock, were offered and sold by the Company pursuant to an effective registration statement on Form S-1, as amended (File No. 333-274610), which was initially filed with the SEC on September 21, 2023, as amended on September 29, 2023, and declared effective by the SEC on September 29, 2023 with an additional registration statement on Form S-1 filed on October 6, 2023 pursuant to Rule 462(c). A final prospectus relating to the Offering was filed with the SEC on October 13, 2023. The closing of the October 2023 Offering contemplated by the Placement Agency Agreement occurred on October 17, 2023.

On October 17, 2023, the Company also entered into a warrant agency agreement with the Company’s transfer agent, Equiniti Trust Company, LLC, who will act as warrant agent for the Company, setting forth the terms and conditions of the Warrants sold in the October 2023 Offering.

Each Warrant has an exercise price of $7.50 per one-half of one (0.5) share of Series J Convertible Preferred Stock, is immediately exercisable and will expire three (3) years from the date of issuance.

There is no established trading market for the Series J Convertible Preferred Stock or the Warrants and we do not expect a market to develop. In addition, we do not intend to list the Series J Convertible Preferred Stock or the Warrants on Nasdaq or any other national securities exchange or any other nationally recognized trading system.

The gross proceeds to the Company from the October 2023 Offering were $2.25 million. Net proceeds were approximately $1.5 million after deducting placement agent fees and commissions and offering expenses payable by the Company. The Company used the net proceeds from the Offering for working capital and for general corporate purposes.

The Series J Convertible Preferred Stock was reflected as mezzanine equity and accreted to reflect its redemption value as of each reporting date. The accretion was be reflected as a deemed dividend adjustment to arrive at net loss attributed to common stockholders for earnings per share calculations.

The Warrants were reflected as a liability and re-measured at fair value as of each reporting date with fair value changes being recorded as non-operating income or expense. The Warrants were valued on day 1 and exceeded the gross proceeds of the offering. This resulted in a day 1 financing expense of $2.7 million.

Understanding the near-term need to raise capital, the Company has recently undertaken steps to reduce our monthly cash burn rate, balanced against our strategic growth initiatives, which will provide more flexibility in anticipation of tougher capital market conditions for microcap companies like Nuwellis. These reductions include, but are not limited to the following: selected job eliminations, a reduction of the salaries for members of senior management, no merit increases to the base salaries of any named executive officer or employee in 2024 for performance provided during the fiscal year ended December 31, 2023, no cash bonuses to any named executive officer or employee in 2024 for performance provided during the fiscal year ended December 31, 2023, a reduction in Board of Director and committee fees, temporary suspension of company 401k match, travel reductions, and reductions to select professional services.

The Company believes that its existing capital resources will be sufficient to support its operating plan through August 31, 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.

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 March 31, 2024, one customer represented 22% net sales. For the three months ended March 31, 2023, two customers each represented 14% and 13% of net sales.

Accounts Receivable: Accounts receivable are unsecured, are recorded at net realizable value, and do not bear interest. Under ASC 326, Current Expected Credit Losses, 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. 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 March 31, 2024, or December 31, 2023. As of March 31, 2024, one customer represented 29% of the accounts receivable balance. As of December 31, 2023, two customers represented 14% and 15% 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)	March 31, 2024			December 31, 2023
Finished Goods	$	651		$	393
Work in Process		198			207
Raw Materials		1,342			1,472
Inventory Reserves		(60	)		(75	)
Total	$	2,131		$	1,997

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.

	March 31
	2024		2023

Stock options		147,316		105,296
Warrants to purchase common stock		2,137,323		19,190
Series F convertible preferred stock		125,857		5,080
Series J convertible preferred stock		2,030		—
Total		2,412,526		129,566

The following table reconciles reported net loss with reported net loss per share for each of the three months ended March 31:

	Three months ended March 31
	2024			2023
(in thousands, except per share amounts)
Net loss	$	(4,330	)	$	(6,485	)
Deemed dividend attributable to Series J Convertible Preferred Stock		541			—
Net loss after deemed dividend		(3,789	)		(6,485	)
Weighted average shares outstanding		6,286			1,126
Basic and diluted loss per share	$	(0.60	)	$	(5.76	)

Subsequent Events: The Company evaluates events through the date the condensed consolidated financial statements are filed for events requiring adjustment to or disclosure in the condensed consolidated financial statements. See note 9 – Subsequent Events for additional disclosures.

Nature of Business and Basis of Presentation, Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
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)	2,412,526	129,566
Reported net loss with reported net loss per share [Abstract]
Net loss	$ (4,330)	$ (6,485)
Deemed dividend attributable to Series J Convertible Preferred Stock	541	0
Net loss after deemed dividend	$ (3,789)	$ (6,485)
Weighted average shares outstanding - basic (in shares)	6,286,298	1,125,993
Weighted average shares outstanding - diluted (in shares)	6,286,298	1,125,993
Basic loss per share (in dollars per share)	$ (0.6)	$ (5.76)
Diluted loss per share (in dollars per share)	$ (0.6)	$ (5.76)
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)	147,316	105,296
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)	2,137,323	19,190
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)	125,857	5,080
Series J 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)	2,030	0

Fair Value of Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2024

Fair Value of Financial Instruments [Abstract]

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
Issuance of Common Stock for exercise of Series I warrants		(7,623	)
October 17, 2023, issuance of Series J warrants		4,965
Exercise of Series J warrants		(536	)
Change in fair value		(1,586	)
Balance at December 31, 2023		2,843
Exercise of Series J warrants		(1,357	)
Change in fair value		(522	)
Balance at March 31, 2024	$	964

Stockholders' Equity	3 Months Ended
Stockholders' Equity	Mar. 31, 2024
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 March 31, 2024, and December 31, 2023, 127 shares of the Series F convertible preferred stock remained outstanding. 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 March 31, 2024. 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 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 2023, the Company issued 657,333 shares of common stock under the At-the-Market Program for gross proceeds of approximately $2.3 million. Net proceeds totaled approximately $2.1 million after deducting the underwriting discounts and commissions and other costs associated with the offering. 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 March 31, 2024. 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 March 31, 2024. 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 March 31, 2024, 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. October 2023 Offering: On October 12, 2023, Nuwellis, Inc. entered into a Placement Agency Agreement with Lake Street Capital Markets, LLC and Maxim Group LLC, pursuant to which the Company issued and sold, in a best efforts registered public offering by the Company, 150,000 units, with each Unit consisting of (A) one share of the Company’s Series J Convertible Redeemable Preferred Stock, par value $0.0001 per share, and (B) one warrant to purchase one-half of one (0.50) share of Series J Convertible Preferred Stock, at a price to the public of $15.00 per Unit, less placement agent fees and commissions. The public offering price of $15.00 per Unit reflects the issuance of the Series J Convertible Preferred Stock with an original issue discount of 40%. The Company is also registering under the Registration Statement (as defined below) an additional 362,933 shares of Series J Convertible Preferred Stock that will be issued, if and when the Company’s Board of Directors declares such dividends, as paid in-kind dividends and the shares of Common Stock issuable upon conversion of the Series J Convertible Preferred Stock issued as PIK dividends. The Units, the shares of Series J Convertible Preferred Stock, the Warrants, the PIK Dividend Shares, the PIK Conversion Shares as well as the shares of Series J Convertible Preferred Stock issuable upon exercise of the Warrants and the shares of the Company’s common stock, par value $0.0001 per share, issuable upon conversion of the Series J Convertible Preferred Stock, were offered and sold by the Company pursuant to an effective registration statement on Form S-1, as amended (File No. 333-274610), which was initially filed with the Securities Exchange Commission on September 21, 2023, as amended on September 29, 2023, and declared effective by the SEC on September 29, 2023 with an additional registration statement on Form S-1 filed on October 6, 2023 pursuant to Rule 462(c). A final prospectus relating to the Offering was filed with the SEC on October 13, 2023. The closing of the Offering contemplated by the Placement Agency Agreement occurred on October 17, 2023. On October 17, 2023, the Company also entered into a warrant agency agreement with the Company’s transfer agent, Equiniti Trust Company, LLC, who will act as warrant agent for the Company, setting forth the terms and conditions of the Warrants sold in this Offering. Each Warrant has an exercise price of $7.50 per one-half of one (0.5) share of Series J Convertible Preferred Stock, is immediately exercisable and will expire three (3) years from the date of issuance. There is no established trading market for the Series J Convertible Preferred Stock or the Warrants and we do not expect a market to develop. In addition, we do not intend to list the Series J Convertible Preferred Stock or the Warrants on The Nasdaq Capital Market or any other national securities exchange or any other nationally recognized trading system. The gross proceeds to the Company from the October 17, 2023, Offering were $2.25 million. Net proceeds were approximately $1.5 million after deducting placement agent fees and commissions and Offering expenses payable by the Company. The Company used the net proceeds from the Offering for working capital and for general corporate purposes. The Series J Convertible Preferred Stock is classified as mezzanine equity and accreted to reflect its redemption value as of each reporting date. The accretion will be reflected as a deemed dividend adjustment to arrive at net loss attributed to common stockholders for earnings per share calculations. The Warrants are recorded as a liability and re-measured at fair value as of each reporting date with fair value changes being recorded as non-operating income or expense. The Warrants were valued on day 1 and exceeded the gross proceeds of the offering. This resulted in a day 1 financing expense of $2.7 million. In connection with the October 2023 offering, the conversion price of the Series F convertible preferred stock was reduced from $25 to $1.01, the per share price to the public in the October 2023 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.

- Definition

The entire disclosure for equity.

+ References

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

+ Details

Insider Trading Arrangement	3 Months Ended
Insider Trading Arrangement	Mar. 31, 2024
Insider Trading Arrangements [Line Items]
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Revenue Recognition (Details)	3 Months Ended
Revenue Recognition (Details)	Mar. 31, 2024	Mar. 31, 2023
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Abstract]
Expected timing of satisfaction, period	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%
Sales Revenue [Member] \| Customer Concentration Risk [Member] \| International [Member] \| Revenue Recognized over Time [Member] \| Maximum [Member]
Revenue, Performance Obligation [Abstract]
Percentage of net sales	6.00%	4.00%

Income Taxes	3 Months Ended
Income Taxes	Mar. 31, 2024
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 March 31, 2024, 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, 2023.

- Definition

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.

+ References

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

+ Details

Subsequent Events (Details) $ / shares in Units, $ in Millions	Apr. 30, 2024 USD ($) Warrant $ / shares shares	Jun. 30, 2023 $ / shares
Stockholders' equity [Abstract]
Warrant exercise price per share (in dollars per share) \| $ / shares		$ 0
Subsequent Event [Member]
Stockholders' equity [Abstract]
Issuance of stock (in shares) \| shares	11,250,000
Aggregate purchase of warrants (in shares) \| shares	16,875,000
Common stock offering price per share (in dollars per share) \| $ / shares	$ 0.24
Number of warrants included in each unit \| Warrant	1
Warrants to purchase common shares (in shares) \| shares	1.50
Warrant exercise price per share (in dollars per share) \| $ / shares	$ 0.4
Warrant expiry period	5 years
Gross proceeds before deducting the placement agent fees and other offering expenses \| $	$ 2.7
Net proceeds from Public Offering \| $	$ 2.1
Subsequent Event [Member] \| Common Warrants [Member]
Stockholders' equity [Abstract]
Warrants to purchase common shares (in shares) \| shares	1
Number of trading days	5 days
Floor price per share (in dollars per share) \| $ / shares	$ 0.06

Stockholders' Equity (Details) $ / shares in Units, $ in Thousands, $ in Millions											3 Months Ended	6 Months Ended	12 Months Ended
	Oct. 17, 2023 USD ($) $ / shares shares	Oct. 17, 2023 AUD ($)	Oct. 12, 2023 shares $ / shares	Jun. 19, 2023 Tranches $ / shares shares	Dec. 08, 2022	Oct. 18, 2022 USD ($) $ / shares shares	Sep. 17, 2021 USD ($) $ / shares shares	Mar. 19, 2021 USD ($) $ / shares shares	Mar. 12, 2019 $ / shares	Nov. 27, 2017 USD ($) $ / shares shares	Mar. 31, 2024 $ / shares shares	Jun. 30, 2023 $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares	Oct. 31, 2022 $ / shares	Sep. 30, 2022 $ / shares	Mar. 23, 2020 $ / shares	Jan. 28, 2020 $ / 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)											$ 0.0001		$ 0.0001
Exercise price of warrants (in dollars per share)												$ 0
Preferred stock, shares outstanding (in shares) \| shares											0		0
Reverse stock split					0.01
Number of common stock warrants converted into common stock (in shares) \| shares												660,046
Number of shares of common stock issued upon conversion of common stock warrants (in shares) \| shares												660,046
Period of warrants expected to vest											48 months
Preferred stock, par value (in dollars per share)											$ 0.0001		$ 0.0001
January 2020 Offering [Member]
Class of Stock Disclosures [Abstract]
Exercise price of warrants (in dollars per share)						$ 25									$ 250
March 2021 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares) \| 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) \| 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) \| shares													657,333
Gross proceeds from public stock offering \| $													$ 2,300
Net proceeds from public stock offering \| $													$ 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) \| shares											0
Warrants to Purchase Common Stock [Member] \| Consultant [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares) \| shares																				33
Exercise price of warrants (in dollars per share)																				$ 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]
Common stock, par value (in dollars per share)				$ 0.0001
Warrants to purchase shares of common stock (in shares) \| shares				1,289,081
Exercise price of warrants (in dollars per share)				$ 3.2996
Number of warrants vested (in shares) \| 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)										$ 189,000											$ 89,040
Number of consecutive trading days considered for expiration											20 days
Number of consecutive trading 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) \| shares										18,000	127		127
Number of shares issuable on conversion of preferred stock (in shares) \| shares										96
Preferred stock, shares outstanding (in shares) \| shares											127		127
Preferred stock, par value (in dollars per share)											$ 0.0001		$ 0.0001
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)									$ 15,750
Series F Convertible Preferred Stock [Member] \| October 2019 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share)																			$ 4,230
Series F Convertible Preferred Stock [Member] \| November 2019 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share)																		$ 2,983
Series F Convertible Preferred Stock [Member] \| January 2020 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share)																	$ 1,650
Exercise price of warrants (in dollars per share)																	$ 900
Series F Convertible Preferred Stock [Member] \| March 2020 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share)																$ 900
Series F Convertible Preferred Stock [Member] \| March 2021 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share)								$ 550
Exercise price of warrants (in dollars per share)								$ 550
Series F Convertible Preferred Stock [Member] \| September 2021 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share)							$ 250
Exercise price of warrants (in dollars per share)							$ 250
Series F Convertible Preferred Stock [Member] \| October 2020 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share)														$ 250
Series F Convertible Preferred Stock [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share)						$ 25								$ 25	$ 250
Series F Convertible Preferred Stock [Member] \| October 2023 Offering [Member]
Class of Stock Disclosures [Abstract]
Conversion price (in dollars per share)			$ 1.01
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) \| 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) \| shares										16
Exercise price of warrants (in dollars per share)										$ 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) \| shares										4
Exercise price of warrants (in dollars per share)										$ 189,000
Series I Preferred Stock [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares) \| shares						23,157,124
Number of shares in one unit (in shares) \| shares						1
Class A Unit [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares) \| shares						209,940
Common stock offering price per share (in dollars per share)						$ 25
Common stock exercise price per share (in dollars per share)						$ 25
Class B Unit [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares) \| shares						23,157,124
Common stock offering price per share (in dollars per share)						$ 0.25
Common stock exercise price per share (in dollars per share)						$ 0
Series J Convertible Preferred Stock [Member] \| October 2023 Offering [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares) \| shares			0.5
Issuance of common stock, net (in shares) \| shares			150,000
Common stock offering price per share (in dollars per share)			$ 15
Number of shares in one unit (in shares) \| shares			1
Preferred stock, par value (in dollars per share)			$ 0.0001
Number of warrants included in each unit \| shares			1
Original issue discount percentage			40.00%
Additional shares issuable upon declaration of dividends (in shares) \| shares			362,933
Common Stock [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Issuance of common stock, net (in shares) \| shares						209,940
Number of shares in one unit (in shares) \| shares						1
Common Stock [Member] \| Series J Convertible Preferred Stock [Member] \| October 2023 Offering [Member]
Class of Stock Disclosures [Abstract]
Common stock, par value (in dollars per share)			$ 0.0001
Warrants [Member] \| October 2023 Offering [Member]
Class of Stock Disclosures [Abstract]
Gross proceeds before deducting placement agent fees and commissions and offering expenses \| $	$ 2,250
Net proceeds after deducting placement agent fees and commissions and offering expenses \| $	$ 1,500
Financing expense \| $		$ 2.7
Warrants [Member] \| Class A Unit [Member] \| October 2022 Offering [Member]
Class of Stock Disclosures [Abstract]
Number of shares in one unit (in shares) \| 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) \| shares						1.5
Warrants [Member] \| Series J Convertible Preferred Stock [Member] \| October 2023 Offering [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares) \| shares	0.5
Exercise price of warrants (in dollars per share)	$ 7.5
Warrants term	3 years

Nature of Business and Basis of Presentation, Nature of Business, Going Concern, Accounts Receivable and Inventories (Details) $ / shares in Units, $ in Thousands, $ in Millions				3 Months Ended		12 Months Ended
	Oct. 17, 2023 USD ($) $ / shares shares	Oct. 17, 2023 AUD ($)	Oct. 12, 2023 shares $ / shares	Mar. 31, 2024 USD ($) Customer $ / shares	Mar. 31, 2023 Customer	Dec. 31, 2023 USD ($) Customer $ / shares	Jun. 30, 2023 $ / shares	Mar. 03, 2023 USD ($)
Going Concern [Abstract]
Accumulated deficit				$ (291,956)		$ (287,626)
Preferred stock, par value (in dollars per share) \| $ / shares				$ 0.0001		$ 0.0001
Common stock, par value (in dollars per share) \| $ / shares				$ 0.0001		$ 0.0001
Exercise price of warrants (in dollars per share) \| $ / shares							$ 0
Merit increases to base salaries of named executive officer or employee				$ 0
Cash bonuses to named executive officer or employee				$ 0
Revenue Recognition [Abstract]
Accounts receivables maximum credit period from invoice date				30 days
Allowance for doubtful accounts				$ 0		$ 0
Inventories [Abstract]
Finished Goods				651		393
Work in Process				198		207
Raw Materials				1,342		1,472
Inventory Reserves				(60)		(75)
Total				$ 2,131		$ 1,997
Warrants [Member] \| October 2023 Offering [Member]
Going Concern [Abstract]
Gross proceeds before deducting placement agent fees and commissions and offering expenses	$ 2,250
Net proceeds after deducting placement agent fees and commissions and offering expenses	$ 1,500
Financing expense		$ 2.7
Series F Convertible Preferred Stock [Member]
Going Concern [Abstract]
Preferred stock, par value (in dollars per share) \| $ / shares				$ 0.0001		$ 0.0001
Series J Convertible Preferred Stock [Member] \| October 2023 Offering [Member]
Going Concern [Abstract]
Issuance of common stock, net (in shares) \| shares			150,000
Number of shares in one unit (in shares) \| shares			1
Preferred stock, par value (in dollars per share) \| $ / shares			$ 0.0001
Number of warrants included in each unit \| shares			1
Warrants to purchase shares of common stock (in shares) \| shares			0.5
Common stock offering price per share (in dollars per share) \| $ / shares			$ 15
Original issue discount percentage			40.00%
Additional shares issuable upon declaration of dividends (in shares) \| shares			362,933
Series J Convertible Preferred Stock [Member] \| Warrants [Member] \| October 2023 Offering [Member]
Going Concern [Abstract]
Warrants to purchase shares of common stock (in shares) \| shares	0.5
Exercise price of warrants (in dollars per share) \| $ / shares	$ 7.5
Warrants term	3 years
Series J Convertible Preferred Stock [Member] \| Common Stock [Member] \| October 2023 Offering [Member]
Going Concern [Abstract]
Common stock, par value (in dollars per share) \| $ / shares			$ 0.0001
Ladenburg Thalmann & Co. [Member]
Going Concern [Abstract]
Percentage of fixed commission rate								3.00%
Net proceeds from public stock offering						$ 2,100
Ladenburg Thalmann & Co. [Member] \| Maximum [Member]
Going Concern [Abstract]
Aggregate offering price								$ 10,000
Net Sales [Member]
Revenue Recognition [Abstract]
Number of major customers \| Customer				1	2
Accounts Receivable [Member]
Revenue Recognition [Abstract]
Number of major customers \| Customer				1		2
Customer One [Member] \| Net Sales [Member] \| Customer Concentration Risk [Member]
Revenue Recognition [Abstract]
Concentration risk percentage				22.00%	14.00%
Customer One [Member] \| Accounts Receivable [Member] \| Customer Concentration Risk [Member]
Revenue Recognition [Abstract]
Concentration risk percentage				29.00%		14.00%
Customer Two [Member] \| Net Sales [Member] \| Customer Concentration Risk [Member]
Revenue Recognition [Abstract]
Concentration risk percentage					13.00%
Customer Two [Member] \| Accounts Receivable [Member] \| Customer Concentration Risk [Member]
Revenue Recognition [Abstract]
Concentration risk percentage						15.00%

Operating Leases	3 Months Ended
Operating Leases	Mar. 31, 2024
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 $34,000. 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.

Revenue Recognition	3 Months Ended
Revenue Recognition	Mar. 31, 2024
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, Belarus, Brazil, Colombia, The Czech Republic, Germany, Greece, Hong Kong, India, Indonesia, Israel, Italy, Panama, Romania, Singapore, Slovak Republic, 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 6% and 4% of net sales for the three months ended March 31, 2024 and 2023, respectively. 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 months ended March 31, 2024 and 2023. The unfulfilled performance obligations related to these extended service plans are included in deferred revenue, which is included in other current liabilities on the condensed 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 received minimal 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.

- Definition

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.

+ References

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

+ Details

Fair Value of Financial Instruments

3 Months Ended

Mar. 31, 2024

Fair Value of Financial Instruments [Abstract]

Fair Value of Financial Instruments

Note 5—Fair Value of Financial Instruments

The Company’s financial instruments consist of cash and cash equivalents 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.

The fair value of the Company’s common stock warrant liability related to the investor warrants issued in the October 2023 and October 2022 public offerings 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
Issuance of Common Stock for exercise of Series I warrants		(7,623	)
October 17, 2023, issuance of Series J warrants		4,965
Exercise of Series J warrants		(536	)
Change in fair value		(1,586	)
Balance at December 31, 2023		2,843
Exercise of Series J warrants		(1,357	)
Change in fair value		(522	)
Balance at March 31, 2024	$	964

- Definition

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.

+ References + Details

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating Activities:
Net loss	$ (4,330)	$ (6,485)
Adjustments to reconcile net loss to cash flows used in operating activities:
Depreciation and amortization	76	86
Stock-based compensation expense	158	181
Change in fair value of warrant liability	(522)	755
Changes in operating assets and liabilities:
Accounts receivable	725	105
Inventory, net	(134)	(81)
Other current assets	21	(81)
Other assets and liabilities	(6)	(16)
Accounts payable and accrued expenses	1,150	(570)
Net cash used in operating activities	(2,862)	(6,106)
Investing Activities:
Additions to intangible assets	0	(85)
Purchases of property and equipment	(29)	(13)
Net cash used in investing activities	(29)	(98)
Financing Activities:
Issuance costs related to 2022 common stock offering	0	(11)
Proceeds from the exercise of Series J Convertible Preferred Warrants	500	0
Net cash provided by (used in) financing activities	500	(11)
Effect of exchange rate changes on cash	(9)	(7)
Net decrease in cash and cash equivalents	(2,400)	(6,222)
Cash and cash equivalents - beginning of period	3,800	17,737
Cash and cash equivalents - end of period	1,400	11,515
Supplemental cash flow information
Issuance of Series J Preferred Stock for exercise of Warrants	1,857	0
Issuance of Common Stock for conversion of Series J Preferred Stock	1,535	0
Deemed dividend on Series J Preferred Stock	$ 541	$ 0

Fair Value of Financial Instruments (Details) - Warrants [Member] - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Roll-Forward of Fair Value of Level 3 Warrants [Roll Forward]
Beginning balance	$ 2,843	$ 6,868
Exercise of warrants	(1,357)
Change in fair value	(522)
Ending balance	$ 964	2,843
October 18, 2022 Series I Warrants Issuance [Member]
Roll-Forward of Fair Value of Level 3 Warrants [Roll Forward]
Issuance of Common Stock for exercise of warrants		(7,623)
Change in fair value		755
October 17, 2023 Series J Warrants Issuance [Member]
Roll-Forward of Fair Value of Level 3 Warrants [Roll Forward]
Issuance		4,965
Exercise of warrants		(536)
Change in fair value		$ (1,586)

Operating Leases (Details) $ in Thousands	3 Months Ended
Operating Leases (Details) $ in Thousands	Mar. 31, 2024 USD ($) ft² $ / ft²
Operating Leases [Abstract]
Area of property leased under operating lease \| ft²	23,000
Monthly rent and common area maintenance charges \| $	$ 34
Annual base rent (per square foot)	10.5
Minimum [Member]
Operating Leases [Abstract]
Annual increase per square foot (in dollars per square foot)	0.32
Maximum [Member]
Operating Leases [Abstract]
Annual increase per square foot (in dollars per square foot)	0.34

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Common Stock [Member] Series I Convertible Preferred Stock [Member]	Common Stock [Member] Series J Convertible Preferred Stock [Member]	Additional Paid in Capital [Member]	Additional Paid in Capital [Member] Series I Convertible Preferred Stock [Member]	Additional Paid in Capital [Member] Series J Convertible Preferred Stock [Member]	Accumulated Other Comprehensive Income [Member]	Accumulated Other Comprehensive Income [Member] Series I Convertible Preferred Stock [Member]	Accumulated Other Comprehensive Income [Member] Series J Convertible Preferred Stock [Member]	Accumulated Deficit [Member]	Accumulated Deficit [Member] Series I Convertible Preferred Stock [Member]	Accumulated Deficit [Member] Series J Convertible Preferred Stock [Member]	Total	Series I Convertible Preferred Stock [Member]	Series J Convertible Preferred Stock [Member]
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	$ 0			181			0			0			181
Stock-based compensation (in shares)	0
Issuance costs related to common stock offering	$ 0			(11)			0			0			(11)
Issuance of common stock from conversion of Convertible Preferred Stock		$ 0			$ 0			$ 0			$ 0			$ 0
Issuance of common stock from conversion of convertible preferred stock (in shares)		10,493
Reclassification of warrants to equity	0			7,623			0			0			7,623
Issuance of common stock from exercise of warrants	$ 0			0			0			0			0
Issuance of common stock from exercise of warrants (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, 2023	$ 1			290,646			(31)			(287,626)			2,990
Balance (in shares) at Dec. 31, 2023	5,682,461
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0			0			0			(4,330)			(4,330)
Unrealized foreign currency translation adjustment	0			0			(9)			0			(9)
Unrealized gain on marketable securities													0
Stock-based compensation	$ 0			158			0			0			158
Stock-based compensation (in shares)	0
Issuance of common stock from conversion of Convertible Preferred Stock			$ 0			$ 1,535			$ 0			$ 0			$ 1,535
Issuance of common stock from conversion of convertible preferred stock (in shares)			1,118,982
Series J Convertible Preferred Stock deemed dividend	$ 0			541			0			0			541
Balance at Mar. 31, 2024	$ 1			$ 292,880			$ (40)			$ (291,956)			$ 885
Balance (in shares) at Mar. 31, 2024	6,801,443

Nature of Business and Basis of Presentation (Policies)

3 Months Ended

Mar. 31, 2024

Nature of Business and Basis of Presentation [Abstract]

Principles of Consolidation

(in thousands)	March 31, 2024			December 31, 2023
Finished Goods	$	651		$	393
Work in Process		198			207
Raw Materials		1,342			1,472
Inventory Reserves		(60	)		(75	)
Total	$	2,131		$	1,997

Loss per Share

	March 31
	2024		2023

Stock options		147,316		105,296
Warrants to purchase common stock		2,137,323		19,190
Series F convertible preferred stock		125,857		5,080
Series J convertible preferred stock		2,030		—
Total		2,412,526		129,566

The following table reconciles reported net loss with reported net loss per share for each of the three months ended March 31:

	Three months ended March 31
	2024			2023
(in thousands, except per share amounts)
Net loss	$	(4,330	)	$	(6,485	)
Deemed dividend attributable to Series J Convertible Preferred Stock		541			—
Net loss after deemed dividend		(3,789	)		(6,485	)
Weighted average shares outstanding		6,286			1,126
Basic and diluted loss per share	$	(0.60	)	$	(5.76	)

Subsequent Events

- Definition

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.

+ References + Details

- Definition

Disclosure of accounting policy for revenue from contract with customer.

+ References

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

+ Details

Stock-Based Compensation

3 Months Ended

Mar. 31, 2024

Stock-Based Compensation [Abstract]

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 March 31
(in thousands)	2024		2023
Selling, general and administrative expense	$	157	$	172
Research and development expense		1		9
Total stock-based compensation expense	$	158	$	181

During the three months ended March 31, 2024 and 2023, under the 2017 Equity Incentive Plan, the 2021 Inducement Plan, and the 2013 Non-Employee Directors’ Equity Incentive Plan, the Company granted 44,330 and 95,113 stock options, respectively, to its directors, officers and employees. Vesting generally occurs over an immediate to 48-month period based on a time-of-service condition. The weighted-average grant date fair value of the stock-options issued during the three months ended March 31, 2024 and 2023 was $0.63 and $7.50 per share, respectively.

The total number of stock options outstanding as of March 31, 2024 and March 31, 2023 was 147,316 and 105,296, respectively.

The weighted-average assumptions used in the Black-Scholes option-pricing model are as follows for the stock options granted during the three months ended March 31, 2024 and 2023:

	Three months ended March 31
	2024			2023
Expected volatility		138.71	%		159.32	%
Expected Life of options (years)		5.51			6.25
Expected dividend yield		0	%		0	%
Risk-free interest rate		3.94	%		4.18	%

During the three months ended March 31, 2024 and 2023, 31,520 and 1,268 stock options vested, respectively, and 7,930 and 302 stock options were expired or forfeited during these periods, respectively. During the three months ended March 31, 2024 and 2023, no options were exercised.

Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Stock-Based Compensation Expense Items [Abstract]
Stock-based compensation expense	$ 158	$ 181
Additional Disclosures [Abstract]
Vesting period	48 months
Outstanding stock options (in shares)	147,316	105,296
Selling, General and Administrative Expense [Member]
Stock-Based Compensation Expense Items [Abstract]
Stock-based compensation expense	$ 157	$ 172
Research and Development Expense [Member]
Stock-Based Compensation Expense Items [Abstract]
Stock-based compensation expense	$ 1	$ 9
Stock Options [Member]
Additional Disclosures [Abstract]
Stock options granted (in shares)	44,330	95,113
Weighted average grant date fair value of stock options issued (in dollars per share)	$ 0.63	$ 7.5
Stock options vested (in shares)	31,520	1,268
Stock options expired or forfeited (in shares)	7,930	302
Exercise of stock options (in shares)	0	0
Weighted Average Assumptions used in Black-Scholes Option Pricing Model [Abstract]
Expected volatility	138.71%	159.32%
Expected Life of options (years)	5 years 6 months 3 days	6 years 3 months
Expected dividend yield	0.00%	0.00%
Risk-free interest rate	3.94%	4.18%

Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2024	May 06, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Document Transition Report	false
Entity File Number	001-35312
Entity Registrant Name	NUWELLIS, INC.
Entity Central Index Key	0001506492
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	68-0533453
Entity Address, Address Line One	12988 Valley View Road
Entity Address, City or Town	Eden Prairie
Entity Address, State or Province	MN
Entity Address, Postal Zip Code	55344
City Area Code	952
Local Phone Number	345-4200
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	NUWE
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		18,051,055

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets
Cash and cash equivalents	$ 1,400	$ 3,800
Accounts receivable	1,226	1,951
Inventories, net	2,131	1,997
Other current assets	440	461
Total current assets	5,197	8,209
Property, plant and equipment, net	681	728
Operating lease right-of-use asset	664	713
Other assets	120	120
TOTAL ASSETS	6,662	9,770
Current liabilities
Accounts payable and accrued liabilities	3,332	2,380
Accrued compensation	725	525
Current portion of operating lease liability	221	216
Other current liabilities	45	51
Total current liabilities	4,323	3,172
Common stock warrant liability	964	2,843
Operating lease liability	488	544
Total liabilities	5,775	6,559
Commitments and contingencies
Mezzanine Equity
Series J Convertible Preferred Stock as of March 31, 2024 and December 31, 2023, par value $0.0001 per share; authorized 600,000 shares, issued and outstanding 82 and 11,950, respectively	2	221
Stockholders' equity
Preferred stock	0	0
Common stock as of March 31, 2024 and December 31, 2023, par value $0.0001 per share; authorized 100,000,000 shares, issued and outstanding 6,801,443 and 5,682,461, respectively	1	1
Additional paid-in capital	292,880	290,646
Accumulated other comprehensive income:
Foreign currency translation adjustment	(40)	(31)
Accumulated deficit	(291,956)	(287,626)
Total stockholders' equity	885	2,990
TOTAL LIABILITIES, CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY	6,662	9,770
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