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Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2018	Aug. 06, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	CHF Solutions, Inc.
Entity Central Index Key	0001506492
Document Type	10-Q
Document Period End Date	Jun. 30, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		7,074,362
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q2

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 6,995	$ 15,595
Accounts receivable	652	545
Inventory	2,315	1,588
Other current assets	205	136
Total current assets	10,167	17,864
Property, plant and equipment, net	576	570
Other assets	195	21
TOTAL ASSETS	10,938	18,455
Current liabilities
Accounts payable and accrued expenses	838	862
Accrued compensation	979	1,021
Other current liabilities	186	208
Total current liabilities	2,003	2,091
Other liabilities	126	126
Total liabilities	2,129	2,217
Commitments and contingencies
Stockholders' equity
Preferred stock	0	0
Common stock as of June 30, 2018 and December 31, 2017, par value $0.0001 per share; authorized 100,000,000 shares, issued and outstanding 4,505,953 and 3,798,929, respectively	0	0
Additional paid-in capital	198,474	197,367
Accumulated other comprehensive income:
Foreign currency translation adjustment	1,226	1,227
Accumulated deficit	(190,891)	(182,356)
Total stockholders' equity	8,809	16,238
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	10,938	18,455
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

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	39,969,390	39,966,220
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)	4,505,953	3,798,929
Common stock, shares outstanding (in shares)	4,505,953	3,798,929
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)	610	3,780
Preferred stock, shares issued (in shares)	610	3,780
Preferred stock, shares outstanding (in shares)	610	3,780

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) [Abstract]
Net sales	$ 1,099	$ 864	$ 2,136	$ 1,765
Costs and expenses:
Cost of goods sold	870	616	1,771	1,130
Selling, general and administrative	3,765	2,420	7,776	4,807
Research and development	643	327	1,122	635
Total costs and expenses	5,278	3,363	10,669	6,572
Loss from operations	(4,179)	(2,499)	(8,533)	(4,807)
Other income (expense):
Other income, net	0	5	0	11
Warrant valuation expense	0	0	0	(67)
Change in fair value of warrant liability	0	37	0	1,466
Total other income, net	0	42	0	1,410
Loss before income taxes	(4,179)	(2,457)	(8,533)	(3,397)
Income tax expense, net	(2)	(1)	(2)	(1)
Net loss	$ (4,181)	$ (2,458)	$ (8,535)	$ (3,398)
Basic and diluted loss per share (in dollars per share)	$ (0.93)	$ (9.38)	$ (2.00)	$ (27.77)
Weighted average shares outstanding - basic and diluted (in shares)	4,494	371	4,263	225
Other comprehensive loss:
Foreign currency translation adjustments	$ (2)	$ (5)	$ (1)	$ (6)
Total comprehensive loss	$ (4,183)	$ (2,463)	$ (8,536)	$ (3,404)

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating Activities
Net loss	$ (8,535)	$ (3,398)
Adjustments to reconcile net loss to cash flows used in operating activities:
Depreciation and amortization expense	115	436
Stock-based compensation expense, net	1,107	281
Change in fair value of warrant liability	0	(1,466)
Warrant valuation expense	0	67
Changes in operating assets and liabilities:
Accounts receivable	(107)	(336)
Inventory	(727)	(187)
Other current assets	(48)	8
Accounts payable and accrued expenses	(283)	(1,103)
Net cash used in operations	(8,478)	(5,698)
Investing Activities:
Purchases of property and equipment	(121)	(20)
Net cash used in investing activities	(121)	(20)
Financing Activities:
Net proceeds from public stock offering	0	8,002
Net proceeds from exercise of warrants	0	1,768
Net proceeds from the sale of preferred stock and warrants	0	184
Net cash provided by financing activities	0	9,954
Effect of exchange rate changes on cash	(1)	(1)
Net (decrease) increase in cash and cash equivalents	(8,600)	4,235
Cash and cash equivalents - beginning of period	15,595	1,323
Cash and cash equivalents - end of period	6,995	5,558
Supplemental schedule of non-cash activities
Warrants issued as inducement to warrant exercise	0	509
Conversion of temporary equity to permanent equity	0	485
Financing fees incurred for subsequent equity financing included in long-term assets and accounts payable	$ 195	$ 0

Nature of Business and Basis of Presentation

6 Months Ended

Jun. 30, 2018

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: CHF Solutions, Inc. (the “Company”) is a medical device company focused on commercializing the Aquadex FlexFlow® System for Aquapheresis® therapy. The Aquadex FlexFlow System (Aquadex) is indicated for temporary (up to eight hours) ultrafiltration treatment of patients with fluid overload who have failed diuretic therapy and extended (longer than 8 hours) ultrafiltration treatment of patients with fluid overload who have failed diuretic therapy and require hospitalization. CHF Solutions, Inc. is a Delaware corporation headquartered in Eden Prairie, Minnesota with wholly owned subsidiaries in Australia, Ireland and Delaware. The Company has been listed on Nasdaq since February 2012.

Prior to July 2016, the Company was focused on developing the C-Pulse® Heart Assist System for treatment of Class III and ambulatory Class IV heart failure. In August 2016, the Company acquired the Aquadex business from a subsidiary of Baxter International, Inc. (“Baxter”), a global leader in the hospital products and dialysis markets (herein referred to as the “Aquadex Business”). On September 29, 2016, the Company announced a strategic refocus of its strategy that included halting all clinical evaluations of its C-Pulse technology to fully focus its resources on its recently acquired Aquadex Business.

On May 23, 2017, the Company announced it was changing its name from Sunshine Heart, Inc. to CHF Solutions, Inc. to more appropriately reflect the direction of its business.

During 2017, the Company’s board of directors and stockholders approved two reverse stock splits (together, the Reverse Stock Splits). Neither reverse stock split changed 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. The first reverse stock split was a 1-for-30 reverse split of the Company’s outstanding common stock that became effective after trading on January 12, 2017. The second reverse stock split was a 1-for-20 reverse split of the Company’s outstanding common stock that became effective after trading on October 12, 2017. All share and per-share amounts have been retroactively adjusted to reflect the Reverse Stock Splits for all periods presented.

Principles of Consolidation: The accompanying 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 10 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 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 financial statements and during the reporting period. Actual results could materially differ from these estimates.

For further information, refer to the consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017.

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, 2017 and 2016 and through June 30, 2018, 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 June 30, 2018, the Company had an accumulated deficit of $190.9 million and it expects to incur losses for the immediate future. To date, the Company has been funded by debt and 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.

The Company became a revenue generating company after acquiring the Aquadex Business in August 2016. The Company expects to incur additional losses in the near-term as it grows the Aquadex Business, including investments in expanding its sales and marketing capabilities, purchasing inventory, manufacturing components, 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 Aquadex. This will require the Company to succeed in training personnel at hospitals and in effectively and efficiently manufacturing, marketing and distributing Aquadex 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 April 24, 2017 and on November 27, 2017, the Company closed on underwritten public equity offerings for net proceeds of approximately $24.2 million after deducting the underwriting discounts and commissions and other costs associated with the offerings (see Note 4 - Equity). After the end of the quarter, on July 3, 2018, the Company closed on an underwritten public offering for net proceeds of approximately $4.7 million after deducting the underwriting discounts and commissions and other costs associated with the offering (see Note 9 - Subsequent Events). The Company will require additional funding to grow its Aquadex Business, which may not be available on terms favorable to the Company, or at all. The Company may receive those funds from the proceeds from future warrant exercises, issuances of equity securities, or other financing transactions. Should warrant exercises not materialize or future capital raising be unsuccessful, the Company may not be able to continue as a going concern. No adjustments have been made relating to the recoverability and classification of recorded asset amounts and classification of liabilities that might be necessary should the Company not continue as a going concern.

Revenue Recognition: The Company recognizes revenue in accordance with Accounting Standards Codification (“ASC”), 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 for additional accounting policies and transition disclosures.

Accounts Receivable: Accounts receivable are unsecured, are recorded at net realizable value, and do not bear interest. The Company makes judgments as to its ability to collect outstanding receivables based upon significant patterns of uncollectability, historical experience, and management’s evaluation of specific accounts and will provide an allowance for credit losses when collection becomes doubtful. The Company performs credit evaluations of its customers’ financial condition on an as-needed basis. Payment is generally due 30 days from the invoice date and accounts past 30 days are individually analyzed for collectability. When all collection efforts have been exhausted, the account is written off against the related allowance. The Company’s accounts receivable have terms that require payment in 30 days. 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 June 30, 2018 or December 31, 2017.

Inventories: Inventories represent finished goods purchased from the Company’s supplier and are recorded as the lower of cost or net realizable value using the first-in-first out method. Inventories consisted of the following:

(in thousands)	June 30, 2018		December 31, 2017
Finished Goods	$	936	$	902
Work in Process		274		217
Raw Materials		1,105		469
Total	$	2,315	$	1,588

Contingent consideration: In connection with the Company’s purchase of the Aquadex Business, the Company has an obligation to pay additional consideration that is contingent upon the occurrence of certain future events (see Note 8 – Commitment and Contingencies). Contingent consideration was recognized at the acquisition date at the estimated fair value of the contingent milestone payments. The fair value of the contingent consideration is remeasured to its estimated fair value at the end of each reporting period, with changes recorded to earnings.

Loss per share: Basic loss 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. The net loss allocable to common stockholders for the three and six months ended June 30, 2017, reflects a $1.0 million increase for the net deemed dividend to preferred stockholders provided in connection with the close of the public offering of Series E Convertible Preferred Stock in April of 2017 (see Note 4 - Equity), representing the intrinsic value of the shares at the time of issuance. In addition, the net loss allocable to common stockholders for the six months ended June 30, 2017, reflects a $1.8 million increase for the net deemed dividend to preferred stockholders provided in connection with the shareholder approval of the Series C and D Convertible Preferred Stock offering in January of 2017 (see Note 4 - Equity), representing the intrinsic value of the shares at the time of issuance. Diluted loss 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. These potentially dilutive shares were excluded from the computation of loss per share as their effect was antidilutive due to the Company’s net loss in each of those periods.

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:

	June 30
	2018	2017
Stock options	2,128,296		32,613
Restricted stock units	135		405
Warrants to purchase common stock	8,522,684		506,335
Series F convertible preferred stock	136,030		-
Total	10,787,145		539,353

The following table reconciles reported net loss with reported net loss per share for the periods ended June 30, 2017:

(in thousands, except per share amounts)	Three months			Six Months
Net loss	$	(2,458	)	$	(3,398	)
Deemed dividend to preferred shareholders (see Note 4)		(1,022	)		(2,851	)
Net loss after deemed dividend		(3,480	)		(6,249	)
Weighted average shares outstanding		371			225
Basic and diluted loss per share	$	(9.38	)	$	(27.77	)

New Accounting Pronouncements: In May 2014, August 2015, March 2016, April 2016 and May 2016, the Financial Accounting Standards Board (“FASB”) issued amended revenue recognition guidance to clarify the principles for recognizing revenue from contracts with customers. The guidance requires an entity to recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which an entity expects to be entitled in exchange for those goods or services. The guidance also requires expanded disclosures relating to the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. Additionally, qualitative and quantitative disclosures are required about customer contracts, significant judgments and changes in judgments, and assets recognized from the costs to obtain or fulfill a contract. The Company adopted this new standard on January 1, 2018, utilizing the modified retrospective approach. There were no impacts to the amount or timing of revenue that the Company had recognized in prior periods. See Note 2 - Revenue Recognition for additional accounting policy and transition disclosures.

In February 2016, the FASB issued updated guidance to improve financial reporting about leasing transactions. This guidance will require organizations that lease assets to recognize on the balance sheet the assets and liabilities for the rights and obligations created by those leases. This guidance is effective for the Company’s annual periods beginning January 1, 2019, and for quarterly periods therein. The Company is evaluating the impact that the adoption of this standard will have, if any, on its consolidated financial statements and disclosures.

Equity	6 Months Ended
Equity	Jun. 30, 2018
Equity [Abstract]
Equity	Note 4 - Equity Series B/B-1 Convertible Preferred Stock: On July 20, 2016, the Company entered into a securities purchase agreement with an institutional investor for an offering of shares of convertible preferred stock and warrants with gross proceeds of approximately $3.5 million in a registered direct offering. The Series B issued under the securities purchase agreement was exchanged for Series B-1 Convertible Preferred Stock on October 30, 2016. The Series B-1 Convertible Preferred Stock was non-voting and was convertible into shares of common stock at the holder’s election at any time. Approximately $1.6 million of the proceeds were allocated to the preferred stock, representing the residual proceeds after the warrants were recorded at fair value (see below.) As of June 30, 2018, and December 31, 2017, all Series B/B-1-Convertible Preferred Stock had been converted into common stock and none were outstanding. Series C and D Convertible Preferred Stock: On October 30, 2016, the Company entered into a securities purchase agreement with an institutional investor for shares of convertible preferred stock and warrants with an aggregate purchase price of $3.8 million in a registered direct offering and simultaneous private placement. The first closing of the transaction occurred on November 3, 2016, whereby the Company received $3.6 million in gross proceeds and the second closing occurred on January 10, 2017, whereby the Company received gross proceeds of $0.2 million. The Series C and D Convertible Preferred Stock issued in the transaction included a contingent beneficial conversion amount of $1.3 million and $0.5 million, respectively, representing the intrinsic value of the shares at the time of issuance. This amount is reflected as an increase to the loss per share allocable to common stockholders in the six-month period ended June 30, 2017 when the contingency for the conversion was resolved with the shareholder approval allowing for the conversion of the preferred stock into common stock. As of June 30, 2018, and December 31, 2017, all shares of the Series C and D Convertible Preferred Stock had been converted into common stock and none were outstanding. Series E Convertible Preferred Stock: On April 24, 2017, the Company closed on an underwritten public offering of common stock, Series E Convertible Preferred Stock, and warrants to purchase shares of common stock for gross proceeds of $9.2 million, which included the full exercise of the underwriter’s over-allotment option to purchase additional shares and warrants. Net proceeds totaled approximately $8.0 million after deducting the underwriting discounts and commissions and other costs associated with the offering. As of June 30, 2018, and December 31, 2017, all shares of the Series E Convertible Preferred Stock had been converted into common stock and none were outstanding. Series F Convertible Preferred Stock: On November 27, 2017, the Company closed on an underwritten public offering of Series F Convertible Preferred Stock (“Series F 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 preferred stock, convertible into shares of the Company’s common stock at a conversion price of $4.50 per share. Each share of Series F preferred stock was accompanied by a Series 1 warrant, which expires on the first anniversary of its issuance, to purchase 223 shares of the Company’s common stock at an exercise price of $4.50 per share, and a Series 2 warrant, which expires on the seventh anniversary of its issuance, to purchase 223 shares of the Company’s common stock at an exercise price of $4.50 per share. The Series F preferred stock and the warrants were immediately separable and were issued separately. The conversion price of the Series F preferred stock will be adjusted in the event of a stock split, combination, reclassification or stock dividend or if the Company consummates a fundamental transaction. The Series F preferred stock also 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 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 preferred stock and the daily dollar trading volume for each trading day during such period exceeds $200,000) (See Note 9 – Subsequent Events). 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 approximately 4.0 million shares of common stock and warrants to purchase approximately 8.0 million shares of common stock were issued in the offering. The Series F Convertible Preferred Stock included a beneficial conversion amount of $8.7 million, representing the intrinsic value of the shares at the time of issuance. As of June 30, 2018 and December 31, 2017, 17,390 and 14,220 shares of the Series F Convertible Preferred Stock had been converted into an aggregate of 3,877,970 and 3,171,060 shares of common stock and 610 and 3,780 remained outstanding, respectively. Placement Agent Fees: In connection with the issuance of the Series B, C and D Convertible Preferred Shares, the Company paid the placement agent an aggregate cash placement fee equal to 6% of the aggregate gross proceeds raised in the offering and issued warrants as described below. In connection with the issuance of the Series E and F Convertible Preferred Shares, the Company provided underwriting discounts and commissions of 9% and 8%, respectively, of the aggregate gross proceeds raised in the offering to the underwriter, and issued no warrants to the underwriter in such transactions. Investor Warrants: In connection with the issuance of the Series B Convertible Preferred Stock in July 2016, the Company issued the investor, at no additional cost, warrants to purchase 6,149 shares of common stock at an exercise price of $564 per share. The warrants were exercisable for 36 months commencing six months from the closing date and were subject to a reduction of the exercise price if the Company subsequently issued common stock or equivalents at an effective price less than the current exercise price of such warrants. Concurrently with the closing of the Series C and D Convertible Preferred Stock and warrant financing on November 3, 2016, the exercise price for these warrants was adjusted to $102 per share. In connection with the issuance of the Series C and D Convertible Preferred Stock in November 2016, the Company issued the investor, at no additional cost, warrants to purchase 35,295 shares of common stock at an exercise price of $108 per share. In connection with the issuance of the Series D Convertible Preferred Stock at the second closing in January 2017, the Company issued the investor, at no additional cost, warrants to purchase 1,961 shares of common stock at an exercise price of $108 per share. The warrants were exercisable for 60 months commencing on the earlier of the day of the receipt of approval of the Company’s stockholders of a proposal to approve the issuance of the shares of common stock underlying the warrants, or the six-month anniversary of the date of issuance. These warrants were subject to a reduction of the exercise price if the Company subsequently issued common stock or equivalents at an effective price less than the current exercise price of such warrants. Warrant Exercise Agreement: On February 15, 2017, the Company entered into a letter agreement with the institutional investors that held the majority of its outstanding warrants (the ‘‘Original Warrants’’), to incent the cash exercise of the investor warrants described above on or before March 31, 2017. In exchange for any such exercise, the Company agreed to provide the investors a replacement warrant (the ‘‘Replacement Warrants’’) to purchase the same number of shares of common stock as were issued upon exercise of the Original Warrants, with an exercise price equal to the consolidated closing bid price of its common stock on the date of issuance. The Replacement Warrants were issued in the same form as the Original Warrants except the exercise prices are not subject to reduction for subsequent equity issuances and the Replacement Warrants do not allow the investor to demand that the Company purchase the Replacement Warrants in the event of a fundamental transaction involving the Company. In connection with this agreement, between February and March 2017, the investors exercised all of the Original Warrants for gross cash proceeds to the Company of $2.0 million, and the Company issued 43,396 Replacement Warrants with exercise prices ranging from $34.6 per share to $99.8 per share. The Company entered into the letter agreement with the investors to incent the exercise of the Original Warrants in order to receive the cash proceeds from the exercise of the Original Warrants and because the exercise of the Original Warrants would allow the Company to remove the warrant liability from its balance sheet and avoid future fair value adjustments and associated volatility in its consolidated financial statements, as the Replacement Warrants are not accounted for as liabilities based on their terms. As of June 30, 2018, and December 31, 2017, there were no Original Warrants outstanding and all Replacement Warrants under the letter agreement had been issued. Placement Agent Warrant: In connection with the issuance of the Series B, C and D Convertible Preferred Stock, the Company issued warrants to the placement agent to purchase an aggregate of 2,605 shares of common stock at exercise prices ranging from $126.0 per share to $810.0 per share. These warrants were issued at no additional cost, were exercisable immediately, and expire five years from the closing of each offering. These warrants do not contain repricing provisions. Warrant Valuation: Both the Original Warrants and placement agent warrants were accounted for as liabilities and were recorded at fair value on the date of issuance. These warrants must be measured and recorded at fair value for each subsequent reporting period that the warrants remain outstanding, and any changes in fair value must be recognized in the consolidated statement of operations. In connection with the warrant exchange agreement described above, the Company remeasured each Original Warrant as of the date of exercise and recorded $1.4 million for the change in fair value of these warrants as an unrealized gain in the accompanying consolidated statement of operations for the six-month period ended June 30, 2017. The Replacement Warrants were valued at $0.5 million using the Black Scholes valuation model with the following assumptions: an expected dividend yield of 0%, expected stock price volatility of 49.65%-50.38%, risk-free interest rates of 1.95%-1.97% and an expected life of 5 years. The warrants have a five-year life and were fully vested at the date of grant. The terms of these warrants do not require them to be accounted for as liabilities and are therefore recorded in equity. As in incentive to early exercise the Original Warrants, the fair value provided to investors through the Replacement Warrants exceeded the fair value of the Original Warrants that was relinquished by the warrant holders by approximately $0.1 million, which has been reflected as an expense in the statement of operations for the six-month period ending June 30, 2017.

Fair Value of Financial Instruments

6 Months Ended

Jun. 30, 2018

Fair Value of Financial Instruments [Abstract]

Fair Value of Financial Instruments

Note 6 - Fair Value of Financial Instruments

The Company’s financial instruments consist of cash and cash equivalents, warrants, and contingent consideration.

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

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

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

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

The fair value of the Company’s common stock warrant liability related to the Original Warrants was calculated using a Monte Carlo valuation model and was classified as Level 3 in the fair value hierarchy. All investor warrants classified as warrant liability were exercised during the six months ended June 30, 2017. The following is a rollforward of the fair value of Level 3 warrants:

Six months ended June 30, 2017 (in thousands)
Balance December 31, 2016	$	1,843
Change in fair value		(1,466	)
Exercise of warrants		(368	)
Ending balance as of June 30, 2017	$	9

The fair value of the Company’s common stock warrant liability related to the placement agent warrants is calculated using a Black Scholes valuation model and is classified as Level 3 in the fair value hierarchy.

Fair values were calculated using the following assumptions:

	As of Dec. 31, 2016			As of Date of Exercise
Risk-free interest rates, adjusted for continuous compounding		1.47/1.96	%		1.45-1.99	%
Term (years)		3.1/5.3			2.84-5.50
Expected volatility		55.3/49.8	%		49.9-58.5	%
Dates and probability of future equity raises	various			various

The fair value of the Company's contingent consideration related to the acquisition of the Aquadex Business from Baxter in August 2016 (see Note 8 – Commitments and Contingencies), was $126,000 as of June 30, 2018 and December 31, 2017. The fair value was initially measured based on the consideration expected to be transferred (probability-weighted), discounted back to present value, and it is considered a Level 3 instrument. The discount rate used was determined at the time of measurement in accordance with accepted valuation methods. The Company measures the liability on a recurring basis using Level 3 inputs including probabilities of payment and projected payment dates. Changes to any of the inputs may result in significantly higher or lower fair value measurements. There were no changes in the fair value of the contingent consideration subsequent to the initial measurement.

All cash equivalents are considered Level 1 measurements for all periods presented. The Company does not have any financial instruments classified as Level 2 or any other classified as Level 3 and there were no movements between these categories during the periods ended June 30, 2018 and December 31, 2017. The Company believes that the carrying amounts of all remaining financial instruments approximate their fair value due to their relatively short maturities.

- 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

Nature of Business and Basis of Presentation (Policies)

6 Months Ended

Jun. 30, 2018

Nature of Business and Basis of Presentation [Abstract]

Principles of Consolidation

For further information, refer to the consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017.

(in thousands)	June 30, 2018		December 31, 2017
Finished Goods	$	936	$	902
Work in Process		274		217
Raw Materials		1,105		469
Total	$	2,315	$	1,588

Contingent Consideration

Loss per Share

	June 30
	2018	2017
Stock options	2,128,296		32,613
Restricted stock units	135		405
Warrants to purchase common stock	8,522,684		506,335
Series F convertible preferred stock	136,030		-
Total	10,787,145		539,353

The following table reconciles reported net loss with reported net loss per share for the periods ended June 30, 2017:

(in thousands, except per share amounts)	Three months			Six Months
Net loss	$	(2,458	)	$	(3,398	)
Deemed dividend to preferred shareholders (see Note 4)		(1,022	)		(2,851	)
Net loss after deemed dividend		(3,480	)		(6,249	)
Weighted average shares outstanding		371			225
Basic and diluted loss per share	$	(9.38	)	$	(27.77	)

New Accounting Pronouncements

- Definition

Disclosure of accounting policy for trade and other accounts receivables. This disclosure may include the basis at which such receivables are carried in the entity's statements of financial position (for example, net realizable value), how the entity determines the level of its allowance for doubtful accounts, when impairments, charge-offs or recoveries are recognized, and the entity's income recognition policies for such receivables, including its treatment of related fees and costs, its treatment of premiums, discounts or unearned income, when accrual of interest is discontinued, how the entity records payments received on nonaccrual receivables and its policy for resuming accrual of interest on such receivables. If the enterprise holds a large number of similar loans, disclosure may include the accounting policy for the anticipation of prepayments and significant assumptions underlying prepayment estimates for amortization of premiums, discounts, and nonrefundable fees and costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(5))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 6
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Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(9))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=84159169&loc=d3e10133-111534

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84158767&loc=d3e18780-107790

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(4))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Nature of Business and Basis of Presentation, Nature of Business, Going Concern, Accounts Receivable and Inventory (Details) $ in Thousands						6 Months Ended		12 Months Ended
	Jul. 03, 2018 USD ($)	Nov. 27, 2017 USD ($)	Oct. 12, 2017	Apr. 24, 2017 USD ($)	Jan. 12, 2017	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($) StockSplit
Nature of Business [Abstract]
Number of reverse stock split \| StockSplit								2
Reverse stock split ratio			20		30
Going Concern [Abstract]
Accumulated deficit						$ (190,891)		$ (182,356)
Net proceeds from public stock offering		$ 24,200		$ 24,200		$ 0	$ 8,002
Accounts Receivable [Abstract]
Accounts receivables maximum credit period from invoice date						30 days
Allowance for doubtful accounts						$ 0		0
Inventory [Abstract]
Finished Goods						936		902
Work in Process						274		217
Raw Materials						1,105		469
Total						$ 2,315		$ 1,588
Subsequent Event [Member]
Going Concern [Abstract]
Net proceeds from public stock offering	$ 4,700

Nature of Business and Basis of Presentation, Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Potential shares of common stock that are not included in the calculation of diluted net loss per share [Abstract]
Potential shares of common stock that are not included in the calculation of diluted net loss per share (in shares)			10,787,145	539,353
Reported net loss with reported net loss per share [Abstract]
Net loss	$ (4,181)	$ (2,458)	$ (8,535)	$ (3,398)
Deemed dividend to preferred shareholders (see Note 4)		(1,022)		(2,851)
Net loss after deemed dividend		$ (3,480)		$ (6,249)
Weighted average shares outstanding (in shares)	4,494,000	371,000	4,263,000	225,000
Basic and diluted loss per share (in dollars per share)	$ (0.93)	$ (9.38)	$ (2.00)	$ (27.77)
Series C and D Convertible Preferred Stock [Member]
Reported net loss with reported net loss per share [Abstract]
Deemed dividend to preferred shareholders (see Note 4)				$ 1,800
Series E Convertible Preferred Stock [Member]
Reported net loss with reported net loss per share [Abstract]
Deemed dividend to preferred shareholders (see Note 4)		$ 1,000		$ 1,000
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)			136,030	0
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)			2,128,296	32,613
Restricted Stock Units [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)			135	405
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)			8,522,684	506,335

Debt, New Loan Agreement (Details) - Revolving Line [Member] - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Line of Credit Facility [Abstract]
Maximum borrowing capacity	$ 1,000
Maximum borrowing capacity percentage of eligible accounts	80.00%
Maturity date	Mar. 31, 2020
Total borrowings outstanding	$ 0	$ 0
Floating Annual Rate [Member]
Line of Credit Facility [Abstract]
Interest rate	1.75%
Prime Rate [Member]
Line of Credit Facility [Abstract]
Interest rate	1.00%

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References + Details

Debt, Warrants (Details)	Jun. 30, 2018 $ / shares shares
Affiliates [Member]
Warrants and Rights Note Disclosure [Abstract]
Warrants issued (in shares) \| shares	55
Exercise price of warrants (in dollars per share)	$ 2,208
Value of warrants (in dollars per share)	$ 1,626
Affiliates [Member] \| Expected Dividend Yield [Member]
Warrants and Rights Note Disclosure [Abstract]
Warrants measurement input	0
Affiliates [Member] \| Expected Stock Price Volatility [Member]
Warrants and Rights Note Disclosure [Abstract]
Warrants measurement input	0.8704
Affiliates [Member] \| Risk-Free Interest Rate [Member]
Warrants and Rights Note Disclosure [Abstract]
Warrants measurement input	0.0220
Affiliates [Member] \| Expected Warrant Option Life [Member]
Warrants and Rights Note Disclosure [Abstract]
Expected warrant option life	6 years 3 months
Silicon Valley Bank [Member]
Warrants and Rights Note Disclosure [Abstract]
Warrants issued (in shares) \| shares	115
Exercise price of warrants (in dollars per share)	$ 3,132
Value of warrants (in dollars per share)	$ 2,316
Silicon Valley Bank [Member] \| Expected Dividend Yield [Member]
Warrants and Rights Note Disclosure [Abstract]
Warrants measurement input	0
Silicon Valley Bank [Member] \| Expected Stock Price Volatility [Member]
Warrants and Rights Note Disclosure [Abstract]
Warrants measurement input	0.8807
Silicon Valley Bank [Member] \| Risk-Free Interest Rate [Member]
Warrants and Rights Note Disclosure [Abstract]
Warrants measurement input	0.0186
Silicon Valley Bank [Member] \| Expected Warrant Option Life [Member]
Warrants and Rights Note Disclosure [Abstract]
Expected warrant option life	6 years 3 months

Equity, Convertible Preferred Stock (Details) - USD ($)							6 Months Ended		12 Months Ended
Equity, Convertible Preferred Stock (Details) - USD ($)	Nov. 27, 2017	Apr. 24, 2017	Jan. 10, 2017	Nov. 03, 2016	Oct. 30, 2016	Jul. 20, 2016	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Class of Stock Disclosures [Abstract]
Proceeds from issuance of convertible preferred stock and Warrants				$ 3,600,000	$ 3,800,000	$ 3,500,000	$ 0	$ 184,000
Preferred stock, shares outstanding (in shares)							0		0
Common stock, shares issued (in shares)							4,505,953		3,798,929
Series B-1 Convertible Preferred Stock [Member]
Class of Stock Disclosures [Abstract]
Proceed from issuance of preferred stock					$ 1,600,000
Series B and B-1 Convertible Preferred Stock [Member]
Class of Stock Disclosures [Abstract]
Preferred stock, shares outstanding (in shares)							0		0
Series C Convertible Preferred Stock [Member]
Class of Stock Disclosures [Abstract]
Beneficial conversion amount			$ 1,300,000
Series D Convertible Preferred Stock [Member]
Class of Stock Disclosures [Abstract]
Proceeds from issuance of convertible preferred stock and Warrants			200,000
Beneficial conversion amount			$ 500,000
Series C and D Convertible Preferred Stock [Member]
Class of Stock Disclosures [Abstract]
Preferred stock, shares outstanding (in shares)							0		0
Series E Convertible Preferred Stock [Member]
Class of Stock Disclosures [Abstract]
Proceed from issuance of preferred stock		$ 9,200,000
Preferred stock, shares outstanding (in shares)							0		0
Net proceeds from issuance of convertible preferred stock		$ 8,000,000
Percentage of underwriting discounts and commissions							9.00%
Series E Convertible Preferred Stock [Member] \| Warrants [Member]
Class of Stock Disclosures [Abstract]
Warrants issued to underwriter (in shares)							0
Series F Convertible Preferred Stock [Member]
Class of Stock Disclosures [Abstract]
Proceed from issuance of preferred stock	$ 18,000,000
Preferred stock, shares outstanding (in shares)							610		3,780
Beneficial conversion amount	8,700,000
Net proceeds from issuance of convertible preferred stock	$ 16,200,000
Conversion price (in dollars per share)	$ 4.50
Number of convertible preferred shares converted (in shares)							17,390		14,220
Number of preferred shares converted to common stock (in shares)	4,000,000						3,877,970		3,171,060
Percentage of volume weighted average price of common stock, minimum	300.00%
Minimum trading volume for each trading day	$ 200,000
Preferred stock issued (in shares)	18,000						610		3,780
Percentage of underwriting discounts and commissions							8.00%
Series F Convertible Preferred Stock [Member] \| Warrants [Member]
Class of Stock Disclosures [Abstract]
Warrants to purchase shares of common stock (in shares)	8,000,000
Warrants issued to underwriter (in shares)							0
Series F Convertible Preferred Stock [Member] \| Warrant Series 1 [Member]
Class of Stock Disclosures [Abstract]
Number of preferred shares converted to common stock (in shares)	223
Exercise price of warrants (in dollars per share)	$ 4.50
Series F Convertible Preferred Stock [Member] \| Warrant Series 2 [Member]
Class of Stock Disclosures [Abstract]
Number of preferred shares converted to common stock (in shares)	223
Exercise price of warrants (in dollars per share)	$ 4.50
Series B, C And D Convertible Preferred Stock [Member]
Class of Stock Disclosures [Abstract]
Percentage of placement fee offered in cash							6.00%

Equity, Warrants (Details) $ / shares in Units, $ in Thousands				2 Months Ended	3 Months Ended		6 Months Ended
	Jan. 10, 2017 USD ($) $ / shares shares	Nov. 03, 2016 USD ($) $ / shares shares	Jul. 26, 2016 USD ($) $ / shares shares	Mar. 31, 2017 USD ($) $ / shares shares	Jun. 30, 2018 USD ($) $ / shares shares	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) $ / shares shares	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Feb. 15, 2017	Dec. 31, 2016
Warrants and Rights Disclosure [Abstract]
Proceeds from exercise of warrants							$ 0	$ 1,768
Change in fair value of warrant liability					$ 0	$ 37	0	1,466
Minimum [Member] \| Risk-Free Interest Rate [Member]
Warrants and Rights Disclosure [Abstract]
Warrants measurement input										0.0145	0.0147
Minimum [Member] \| Expected Warrant Option Life [Member]
Warrants and Rights Disclosure [Abstract]
Expected warrant option life										2 years 10 months 2 days	3 years 1 month 6 days
Maximum [Member] \| Risk-Free Interest Rate [Member]
Warrants and Rights Disclosure [Abstract]
Warrants measurement input										0.0199	0.0196
Maximum [Member] \| Expected Warrant Option Life [Member]
Warrants and Rights Disclosure [Abstract]
Expected warrant option life										5 years 6 months	5 years 3 months 18 days
Replacement Warrants [Member]
Warrants and Rights Disclosure [Abstract]
Warrants outstanding					$ 500		$ 500
Replacement Warrants [Member] \| Expected Dividend Yield [Member]
Warrants and Rights Disclosure [Abstract]
Warrants measurement input					0		0
Replacement Warrants [Member] \| Expected Warrant Option Life [Member]
Warrants and Rights Disclosure [Abstract]
Expected warrant option life					5 years		5 years
Replacement Warrants [Member] \| Minimum [Member] \| Expected Stock Price Volatility [Member]
Warrants and Rights Disclosure [Abstract]
Warrants measurement input					0.4965		0.4965
Replacement Warrants [Member] \| Minimum [Member] \| Risk-Free Interest Rate [Member]
Warrants and Rights Disclosure [Abstract]
Warrants measurement input					0.0195		0.0195
Replacement Warrants [Member] \| Maximum [Member] \| Expected Stock Price Volatility [Member]
Warrants and Rights Disclosure [Abstract]
Warrants measurement input					0.5038		0.5038
Replacement Warrants [Member] \| Maximum [Member] \| Risk-Free Interest Rate [Member]
Warrants and Rights Disclosure [Abstract]
Warrants measurement input					0.0197		0.0197
Series B Convertible Preferred Stock [Member] \| Investor Warrants [Member]
Warrants and Rights Disclosure [Abstract]
Warrants issuance cost			$ 0
Warrants to purchase shares of common stock (in shares) \| shares			6,149
Exercise price of warrants (in dollars per share) \| $ / shares			$ 564
Warrants exercisable period							36 months
Period warrants became exercisable from closing date							6 months
Series D Convertible Preferred Stock [Member] \| Investor Warrants [Member]
Warrants and Rights Disclosure [Abstract]
Warrants issuance cost	$ 0
Warrants to purchase shares of common stock (in shares) \| shares	1,961
Exercise price of warrants (in dollars per share) \| $ / shares	$ 108
Warrants exercisable period							60 months
Period warrants became exercisable from closing date							6 months
Series C and D Convertible Preferred Stock [Member] \| Investor Warrants [Member]
Warrants and Rights Disclosure [Abstract]
Warrants issuance cost		$ 0
Warrants to purchase shares of common stock (in shares) \| shares		35,295
Exercise price of warrants (in dollars per share) \| $ / shares		$ 108
Adjusted exercise price of warrants (in dollars per share) \| $ / shares		$ 102
Series B, C And D Convertible Preferred Stock [Member] \| Placement Agent Warrant [Member]
Warrants and Rights Disclosure [Abstract]
Warrants issuance cost							$ 0
Warrants to purchase shares of common stock (in shares) \| shares					2,605		2,605
Expiration term of warrants							5 years
Series B, C And D Convertible Preferred Stock [Member] \| Placement Agent Warrant [Member] \| Minimum [Member]
Warrants and Rights Disclosure [Abstract]
Exercise price of warrants (in dollars per share) \| $ / shares					$ 126.0		$ 126.0
Series B, C And D Convertible Preferred Stock [Member] \| Placement Agent Warrant [Member] \| Maximum [Member]
Warrants and Rights Disclosure [Abstract]
Exercise price of warrants (in dollars per share) \| $ / shares					$ 810.0		$ 810.0
Warrant Exercise Agreement [Member] \| Original Warrants [Member]
Warrants and Rights Disclosure [Abstract]
Proceeds from exercise of warrants				$ 2,000
Warrants outstanding					$ 0		$ 0		$ 0
Relinquished amount of warrants								$ 100
Warrant Exercise Agreement [Member] \| Replacement Warrants [Member]
Warrants and Rights Disclosure [Abstract]
Warrants to purchase shares of common stock (in shares) \| shares				43,396
Warrant Exercise Agreement [Member] \| Replacement Warrants [Member] \| Minimum [Member]
Warrants and Rights Disclosure [Abstract]
Exercise price of warrants (in dollars per share) \| $ / shares				$ 34.6
Warrant Exercise Agreement [Member] \| Replacement Warrants [Member] \| Maximum [Member]
Warrants and Rights Disclosure [Abstract]
Exercise price of warrants (in dollars per share) \| $ / shares				$ 99.8

Fair Value of Financial Instruments (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Feb. 15, 2017	Dec. 31, 2016
Fair value of Level 3 [Roll Forward]
Change in fair value	$ 0	$ 37	$ 0	$ 1,466
Fair Value Transfers between levels [Abstract]
Level 1 to Level 2 Asset Transfers	0		0		$ 0
Level 2 to Level 1 Asset Transfers	0		0		0
Level 1 to Level 2 Liability Transfers	0		0		0
Level 2 to Level 1 Liability Transfers	0		0		0
Aquadex Product Line [Member]
Fair Value Transfers between levels [Abstract]
Fair value of contingent consideration	$ 126		$ 126		$ 126
Minimum [Member] \| Risk-Free Interest Rates, Adjusted for Continuous Compounding [Member]
Fair Value Assumptions [Abstract]
Fair value assumptions measurement input						0.0145	0.0147
Minimum [Member] \| Term [Member]
Fair Value Assumptions [Abstract]
Term						2 years 10 months 2 days	3 years 1 month 6 days
Minimum [Member] \| Expected Volatility [Member]
Fair Value Assumptions [Abstract]
Fair value assumptions measurement input						0.499	0.498
Maximum [Member] \| Risk-Free Interest Rates, Adjusted for Continuous Compounding [Member]
Fair Value Assumptions [Abstract]
Fair value assumptions measurement input						0.0199	0.0196
Maximum [Member] \| Term [Member]
Fair Value Assumptions [Abstract]
Term						5 years 6 months	5 years 3 months 18 days
Maximum [Member] \| Expected Volatility [Member]
Fair Value Assumptions [Abstract]
Fair value assumptions measurement input						0.585	0.553
Level 3 [Member]
Fair value of Level 3 [Roll Forward]
Balance				1,843
Change in fair value				(1,466)
Exercise of warrants				(368)
Ending balance		$ 9		$ 9

Revenue Recognition	6 Months Ended
Revenue Recognition	Jun. 30, 2018
Revenue Recognition [Abstract]
Revenue Recognition	Note 2 – Revenue Recognition Net Sales The Company sells its products in the United States primarily through a direct sales force. 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 the United Kingdom, Italy, Spain, Germany, and Southeast Asia. The majority of these distributors resell the Company’s products to hospitals and clinics in their respective geographies. Revenue from product sales are 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 includes shipment and handling fees charged to customers. Revenue is measured as the amount of consideration the Company expects 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 that are recognized over time. This revenue represents less than 1% of net sales for the periods ended June 30, 2018. The unfulfilled performance obligations related to these extended service plans is included in deferred revenue in the amount of $30,000 and $38,000 as of June 30, 2018 and December 31, 2017, respectively. Deferred revenue is included in other current liabilities on the condensed consolidated balance sheet. The majority of the deferred revenue is expected to be recognized within one year. Sales taxes and value added taxes in foreign jurisdictions that are collected from customers and remitted to governmental authorities are accounted for on a net basis and therefore are excluded from net sales. Revenue includes shipment and handling fees charged to customers. Shipping and handling costs associated with outbound freight after control over a product has transferred to a customer are accounted for as a fulfillment cost and are included in cost of goods sold. Product Returns: The Company offers customers a limited right of return for its product in case of non-conformity or performance issues. The Company estimates the amount of its product sales that may be returned by its customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized. The Company currently estimates product return liabilities using available industry data and its own historical sales and returns information. The Company has not received any returns to date and believes that future returns of its products will be minimal. Therefore, revenue recognized is not currently impacted by variable consideration related to product returns.

Debt	6 Months Ended
Debt	Jun. 30, 2018
Debt [Abstract]
Debt	Note 3 - Debt On August 5, 2016, the Company entered into a loan and security agreement with Silicon Valley Bank (the “Bank”) for a $1.0 million revolving line of credit (the “Revolving Line”). Under the Revolving Line, the Company may borrow the lesser of $1.0 million or 80% of its eligible accounts (subject to customary exclusions), minus the outstanding principal balance of any advances under the Revolving Line. Advances under the Revolving Line, if any, accrue interest at a floating annual rate equal to 1.75% or 1.0% above the prime rate, depending on liquidity factors. The loan agreement contains customary representations, as well as customary affirmative and negative covenants. Outstanding borrowings, if any, are collateralized by all of the Company’s assets, excluding intellectual property which is subject to a negative pledge. Advances under the Revolving Line are subject to various conditions precedent, including compliance with financial covenants relating to net liquidity relative to monthly cash burn. The Revolving Line expires March 31, 2020. There were no borrowings outstanding under this facility as of June 30, 2018 or December 31, 2017. Warrants: In connection with the funding of term loans under prior agreements, the Company issued warrants to purchase 115 shares of common stock at an exercise price of $3,132 per share and warrants to purchase 55 shares of common stock at an exercise price of $2,208 per share to the Bank and one of its affiliates. The Company valued these warrants at $2,316 per share and $1,626 per share, respectively, utilizing the Black Scholes valuation model and the following assumptions: an expected dividend yield of 0%, an expected stock price volatility of 88.07% and 87.04%, a risk-free interest rate of 1.86% and 2.20%, and an expected life of 6.25 years. The warrants were fully vested on the date of grant and expire on February 2025, and June 2025, respectively.

Income Taxes	6 Months Ended
Income Taxes	Jun. 30, 2018
Income Taxes [Abstract]
Income Taxes	Note 7 – Income Taxes The Company provides for a valuation allowance when it is more likely than not that it will not realize a portion of the deferred tax assets. The Company has established a full valuation allowance for U.S. and foreign deferred tax assets due to the uncertainty that enough taxable income will be generated in those taxing jurisdictions to utilize the assets. Therefore, the Company has not reflected any benefit of such deferred tax assets in the accompanying consolidated financial statements. As of June 30, 2018, 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, 2017.

Commitments and Contingencies	6 Months Ended
Commitments and Contingencies	Jun. 30, 2018
Commitments and Contingencies [Abstract]
Commitments and Contingencies	Note 8 - Commitments and Contingencies Leases: The Company leases office space under a non-cancelable operating lease that expires in March 2019. The lease contains provisions for future annual inflationary adjustments. Rent expense is recognized using the straight-line method over the term of the lease. Employee Retirement Plan: The Company has a 401(k)-profit sharing plan that provides retirement benefit to substantially all full-time U.S. employees. Eligible employees may contribute a percentage of their annual compensation, subject to Internal Revenue Service limitations, with the Company matching a portion of the employee’s contributions at the discretion of the Company. Contingent Consideration: As part of the acquisition of the Aquadex Business from Baxter in August 2016, the Company agreed that if it disposes of any of the Aquadex assets for a price that exceeds $4.0 million within three years of the closing, it will pay Baxter 40% of the amount of such excess. In addition, it also agreed that if shares of its common stock cease to be publicly traded on the Nasdaq Capital Market, Baxter has the option to require the Company to repurchase, in cash, all or any part of the common shares held by Baxter at a price equal to their fair market value, as determined by a third-party appraiser.

Subsequent Events	6 Months Ended
Subsequent Events	Jun. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	Note 9- Subsequent Events On July 3, 2018, the Company closed on an underwritten public offering of 2,547,169 shares of its common stock at a public offering price of $2.12 per share, for gross proceeds of $5.4 million, including the full exercise of the underwriters’ over-allotment option to purchase additional shares of the Company’s common stock, prior to deducting underwriting discounts and commissions and offering expenses payable by CHF Solutions (the “July 2018 Offering”). In connection with the July 2018 Offering, and to induce certain institutional investors who hold warrants issued by the Company in November 2017 (“November 2017 Warrants”) to participate in the July 2018 Offering, the Company entered into letter agreements with such institutional investors (collectively, the “Warrant Reprice Agreements”). Pursuant to the terms of the Warrant Reprice Agreements, the Company agreed, effective July 3, 2018, to (a) reduce the per share exercise price of the November 2017 Warrants held by such institutional investors (the “Repriced Warrants”) to $2.12 and (b) extend the expiration date of the Repriced Warrants that were to expire on November 27, 2018 to November 27, 2019. The number of shares underlying the Repriced Warrants after the price reduction did not change. The Repriced Warrants are exercisable for 7,760,400 shares of common stock in the aggregate, of which, following such amendment, half expire on November 27, 2019 and half expire on November 27, 2024. Additionally, the Company’s outstanding Series F preferred stock is subject to full-ratchet anti-dilution protection in the event the Company sells any common stock at a price lower than the then-conversion price of the Series F preferred stock. As a result of the July 2018 Offering, effective July 3, 2018, the conversion price of the Series F preferred stock was reduced from $4.50 to $2.12, the per share price to public in the July 2018 Offering. On August 3, the Company amended its office and manufacturing space lease agreement for its facility in Eden Prairie, Minnesota, to extend it for an additional thirty-six months beyond the previous expiration date. This amended lease agreement expires in March 31, 2022.

Revenue Recognition (Details) - USD ($) $ in Thousands	6 Months Ended
Revenue Recognition (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Revenue, Performance Obligation [Abstract]
Deferred revenue	$ 30	$ 38
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing of satisfaction, period	1 year
Sales Revenue [Member] \| Maximum [Member] \| ASC 606 [Member]
Revenue, Performance Obligation [Abstract]
Percentage of net sales	1.00%

Stock-Based Compensation (Details) - USD ($) $ in Thousands	6 Months Ended
Stock-Based Compensation (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Stock-Based Compensation Expense Items [Abstract]
Stock-based compensation expense	$ 1,107	$ 283
Selling, General and Administrative Expense [Member]
Stock-Based Compensation Expense Items [Abstract]
Stock-based compensation expense	1,006	245
Research and Development Expense [Member]
Stock-Based Compensation Expense Items [Abstract]
Stock-based compensation expense	$ 101	$ 38

Commitments and Contingencies - (Details) - Aquadex Product Line [Member] - USD ($) $ in Thousands	1 Months Ended	6 Months Ended
	Aug. 31, 2016	Jun. 30, 2018
Contingent Consideration [Abstract]
Sale or disposal of business assets threshold for contingent consideration	$ 4,000
Percentage of additional payments on disposes of business assets	40.00%
Maximum [Member]
Contingent Consideration [Abstract]
Contingent consideration period		3 years

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Millions	Aug. 03, 2018	Jul. 03, 2018	Nov. 27, 2017
Series F Convertible Preferred Stock [Member]
Subsequent Event [Line Items]
Conversion price (in dollars per share)			$ 4.50
Subsequent Event [Member]
Subsequent Event [Line Items]
Common stock issued (in shares)		2,547,169
Public offering price (in dollars per share)		$ 2.12
Gross proceeds from public stock offering		$ 5.4
Warrants exercisable (in shares)		7,760,400
Renewal lease term	36 months
Lease expiration date	Mar. 31, 2022
Subsequent Event [Member] \| Series F Convertible Preferred Stock [Member]
Subsequent Event [Line Items]
Conversion price (in dollars per share)		$ 2.12