Avinger (AVGR) 10-Q 15 May 24 2024 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2024	May 03, 2024
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	001-36817
Entity Registrant Name	AVINGER, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-8873453
Entity Address, Address Line One	400 Chesapeake Drive
Entity Address, City or Town	Redwood City
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94063
City Area Code	650
Local Phone Number	241-7900
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	AVGR
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 (in shares)		1,702,226
Entity Central Index Key	0001506928
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false

Condensed Balance Sheets (Curre

Condensed Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 7,174	$ 5,275
Accounts receivable, net of allowance for doubtful accounts of $56 and $41 at March 31, 2024 and December 31, 2023, respectively	1,377	1,014
Inventories, net	4,562	5,298
Prepaid expenses and other current assets	1,008	575
Total current assets	14,121	12,162
Right of use asset	1,991	1,102
Property and equipment, net	523	487
Other assets	225	19
Total assets	16,860	13,770
Current liabilities:
Accounts payable	747	777
Accrued compensation	2,523	2,311
Preferred stock dividends payable	65	0
Accrued expenses and other current liabilities	822	817
Leasehold liability, current portion	1,156	1,102
Borrowings	14,751	14,293
Total current liabilities	20,064	19,300
Leasehold liability, long-term portion	835	0
Other long-term liabilities	15	672
Total liabilities	20,914	19,972
Commitments and contingencies (Note 6)
Stockholders’ deficit:
Shares issued and outstanding: 19,229 and 62,881 at March 31, 2024 and December 31, 2023, respectively; aggregate liquidation preference related to Series E and Series F convertible preferred stock of $7,338 at March 31, 2024 and $62,796 at December 31, 2023 related to Series A and Series E convertible preferred stock	0	0
Shares issued and outstanding: 1,586,434 and 1,279,928 at March 31, 2024 and December 31, 2023, respectively	2	1
Additional paid-in capital	422,157	414,493
Accumulated deficit	(426,213)	(420,696)
Total stockholders’ deficit	(4,054)	(6,202)
Total liabilities and stockholders’ deficit	$ 16,860	$ 13,770

Condensed Balance Sheets (Cur_2

Condensed Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Accounts Receivable, Allowance for Credit Loss, Current	$ 56	$ 41
Preferred Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.001	$ 0.001
Preferred Stock, Shares Authorized (in shares)	5,000,000	5,000,000
Preferred Stock, Shares Issued (in shares)	19,229	62,881
Preferred Stock, Shares Outstanding (in shares)	19,229	62,881
Preferred Stock, Liquidation Preference, Value	$ 7,338	$ 62,796
Common Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.001
Common Stock, Shares Authorized (in shares)	100,000,000	100,000,000
Common Stock, Shares, Issued (in shares)	1,586,434	1,279,928
Common Stock, Shares, Outstanding (in shares)	1,586,434	1,279,928

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenues	$ 1,859	$ 1,888
Cost of revenues	1,516	1,252
Gross profit	343	636
Operating expenses:
Research and development	1,062	1,356
Selling, general and administrative	4,370	3,538
Total operating expenses	5,432	4,894
Loss from operations	(5,089)	(4,258)
Interest expense, net	(416)	(392)
Other (expense) income, net	(12)	6
Net loss and comprehensive loss	(5,517)	(4,644)
Accretion of preferred stock dividends	(65)	(1,218)
Gain on exchange of Series A for Series A-1 convertible preferred stock	1,908	0
Net loss applicable to common stockholders	$ (3,674)	$ (5,862)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (2.49)	$ (10.7)
Weighted average common shares used to compute net loss per share, basic and diluted (in shares)	1,477	548

Condensed Statements of Stockho

Condensed Statements of Stockholders' Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Preferred Stock [Member] Private Placement [Member]	Preferred Stock [Member] Series A-1 Preferred Stock [Member]	Preferred Stock [Member]	Common Stock [Member] Private Placement [Member]	Common Stock [Member]	Additional Paid-in Capital [Member] Private Placement [Member]	Additional Paid-in Capital [Member] Series A-1 Preferred Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member] Private Placement [Member]	Retained Earnings [Member] Series A-1 Preferred Stock [Member]	Retained Earnings [Member]	Private Placement [Member]	Series A-1 Preferred Stock [Member]	Total
Balance (in shares) at Dec. 31, 2022			60,961		522,177
Balance at Dec. 31, 2022					$ 8			$ 406,514			$ (402,376)			$ 4,146
Issuance of common stock in public offerings, net of commissions and issuance costs (in shares)			0		794
Issuance of common stock in public offerings, net of commissions and issuance costs			$ 0		$ 0			(21)			0			(21)
Exercise of pre-funded warrants for common stock (in shares)			0		49,858
Exercise of pre-funded warrants for common stock			$ 0		$ 1			(1)			0			0
Issuance of common stock upon vesting of restricted stock units (in shares)			0		2,294
Issuance of common stock upon vesting of restricted stock units					$ 0			0			0			0
Employee stock-based compensation			$ 0		0			245			0			245
Accretion of Series A preferred stock dividends			0		0			(1,218)			0			(1,218)
Net and comprehensive loss			$ 0		$ 0			0			(4,644)			(4,644)
Balance (in shares) at Mar. 31, 2023			60,961		575,123
Balance at Mar. 31, 2023					$ 9			405,519			(407,020)			(1,492)
Balance (in shares) at Dec. 31, 2023			62,881		1,279,928
Balance at Dec. 31, 2023			$ 0		$ 1			414,493			(420,696)			(6,202)
Issuance of common stock in public offerings, net of commissions and issuance costs (in shares)	7,224	10,000		75,327
Issuance of common stock in public offerings, net of commissions and issuance costs		$ 0		$ 0		$ 6,880	$ 0		$ 0	$ 0		$ 6,880	$ 0
Employee stock-based compensation					0			1,096			0			1,096
Accretion of Series A preferred stock dividends			0		0			(65)			0			(65)
Net and comprehensive loss					0			0			(5,517)			(5,517)
Issuance of common stock warrants in connection with the Private Placement			$ 0		$ 0			127			0			127
Cancellation of Series A preferred stock (in shares)			(60,876)		0
Cancellation of Series A preferred stock			$ 0		$ 0			0			0			0
Issuance of common stock upon vesting of restricted stock awards (in shares)			0		368,503
Issuance of common stock upon vesting of restricted stock awards			$ 0		$ 1			0			0			1
Net share settlement of restricted stock awards in satisfaction of tax obligations (in shares)			0		(137,324)
Net share settlement of restricted stock awards in satisfaction of tax obligations			$ 0		$ 0			(374)			0			(374)
Balance (in shares) at Mar. 31, 2024			19,229		1,586,434
Balance at Mar. 31, 2024					$ 2			$ 422,157			$ (426,213)			$ (4,054)

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities
Net loss	$ (5,517)	$ (4,644)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	83	72
Amortization of debt issuance costs and debt discount	16	21
Stock-based compensation	1,096	245
Noncash interest expense and other charges	442	486
Change in right of use asset	4	14
Provision for excess and obsolete inventories	34	179
Other	15	(50)
Changes in operating assets and liabilities:
Accounts receivable	(378)	94
Inventories	584	(469)
Prepaid expenses and other current assets	(433)	(616)
Other assets	(210)	2
Accounts payable	(30)	(114)
Accrued compensation	212	367
Accrued expenses and other current liabilities	5	68
Other long-term liabilities	(657)	133
Net cash used in operating activities	(4,734)	(4,212)
Cash flows from investing activities
Investing activities	0	0
Net cash used in investing activities	0	0
Cash flows from financing activities
Net share settlement on restricted stock awards in satisfaction of tax obligations	374	0
Net cash (used in) provided by financing activities	6,633	(21)
Net change in cash and cash equivalents	1,899	(4,233)
Cash and cash equivalents, beginning of period	5,275	14,603
Cash and cash equivalents, end of period	7,174	10,370
Supplemental disclosure of cash flow information
Increase to right of use asset and leasehold liability arising from lease amendment	1,177	0
Accretion of preferred stock dividends	65	1,218
Reclassification of other long-term liabilities to accrued compensation	0	638
Transfers between inventory and property and equipment	118	(62)
Common Stock [Member]
Cash flows from financing activities
Proceeds from the issuance of common stock and convertible preferred stock, net of commissions and issuance costs	7,007	0
Preferred Stock [Member]
Cash flows from financing activities
Proceeds from the issuance of common stock and convertible preferred stock, net of commissions and issuance costs	$ 0	$ (21)

Note 1 - Organization

Note 1 - Organization	3 Months Ended
	Mar. 31, 2024
Notes to Financial Statements
Nature of Operations [Text Block]	1. Organization Organization, Nature of Business Avinger, Inc. (the “Company”), a Delaware corporation, was incorporated in March 2007. The Company designs, manufactures and sells image-guided, catheter-based systems that are used by physicians to treat patients with peripheral artery disease (“PAD”). Patients with PAD have a build-up of plaque in the arteries that supply blood to areas away from the heart, particularly the pelvis and legs. The Company manufactures and sells a suite of products in the United States (“U.S.”) and in select international markets. The Company has developed its Lumivascular platform, which integrates optical coherence tomography (“OCT”) visualization with interventional catheters and is the industry’s only system that provides real-time intravascular imaging during the treatment portion of PAD procedures. The Company’s Lumivascular platform consists of a capital component, Lightbox consoles, as well as a variety of disposable catheter products. The Company’s current catheter products include Ocelot, Tigereye and Tigereye ST, which are designed to allow physicians to penetrate a total blockage in an artery, known as a chronic total occlusion (“CTO”). The Company also has image-guided atherectomy products, Pantheris, Pantheris SV and Pantheris LV, which are designed to allow physicians to precisely remove arterial plaque in PAD patients. The Company is in the process of developing next-generation CTO crossing devices to target coronary CTO markets. The Company is located in Redwood City, California. Liquidity Matters The accompanying financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. The Financial Accounting Standards Board (“FASB”) Accounting Standards Update (“ASU”) No. 2014-15, Presentation of Financial Statements - Going Concern (Subtopic 205-40) In the course of its activities, the Company has incurred losses and negative cash flows from operations since its inception. On March 5, 2024, the Company entered into a financing as part of a broader strategic collaboration with Zylox-Tonbridge Medical Technology Co., Ltd. (“Zylox-Tonbridge”) in which the Company received an aggregate of $7.5 million before any commissions, legal and accounting fees, and other ancillary expenses as described more fully below. As of March 31, 2024, the Company had an accumulated deficit of $426.2 million. The Company expects to incur losses for the foreseeable future. The Company believes that its cash and cash equivalents of $7.2 million at March 31, 2024, together with debt and other financing activities and expected revenues from operations will be sufficient to allow the Company to fund its current operations through the second quarter of 2024. The Company received net proceeds of approximately $6.5 million from the sale of its common stock under an At The Market Offering Agreement from the time of activation through March 31, 2024. The Company may seek to raise additional funds in future equity offerings to meet its operational needs and capital requirements for product development, clinical trials and commercialization or other strategic objectives. The Company can provide no assurance that it will be successful in raising funds pursuant to additional equity or debt financings or that such funds will be raised at prices that do not create substantial dilution for its existing stockholders. Given the volatility in the Company’s stock price, any financing that the Company may undertake in the next twelve months could cause substantial dilution to its existing stockholders, and there can be no assurance that the Company will be successful in acquiring additional funding at levels sufficient to fund its various endeavors. These conditions raise substantial doubt about the Company’s ability to continue as a going concern. In addition, the macroeconomic environment has in the past resulted in and could continue to result in reduced consumer and investor confidence, instability in the credit and financial markets, volatile corporate profits and reduced business and consumer spending, which could increase the cost of capital and/or limit the availability of capital to the Company. If the Company is unable to raise additional capital in sufficient amounts or on terms acceptable to it, the Company may have to significantly reduce its operations or delay, scale back or discontinue the development and sale of one or more of its products. The financial statements do not include any adjustments that might result from the outcome of this uncertainty. The Company’s ultimate success will largely depend on its continued development of innovative medical technologies, its ability to successfully commercialize its products and its ability to raise significant additional funding. Additionally, due to the substantial doubt about the Company’s ability to continue operating as a going concern and the “Material Adverse Change” clause in the Loan Agreement with CRG Partners III L.P. and certain of its affiliated funds (collectively “CRG”), the entire amount of outstanding borrowings at March 31, 2024 and December 31, 2023 has been classified as current in these financial statements. CRG has not purported that an Event of Default (as defined in the Loan Agreement) has occurred due to a Material Adverse Change. Currently substantially all of our cash and cash equivalents are held at a single financial institution, First Citizens Bank, which acquired our prior banking partner, Silicon Valley Bank, in March 2023. On March 10, 2023, the Federal Deposit Insurance Corporation announced that Silicon Valley Bank had been closed by the California Department of Financial Protection and Innovation. While we have regained access to our accounts at Silicon Valley Bank, now a division of First Citizens Bank, and are evaluating our banking relationships, future disruptions of financial institutions where we bank or have credit arrangements, or disruptions of the financial services industry in general, could adversely affect our ability to access our cash and cash equivalents. If we are unable to access our cash and cash equivalents as needed, our financial position and ability to operate our business will be adversely affected. Public Offerings At The Market Offering Agreement On May 20, 2022, the Company entered into an At The Market Offering Agreement (the “ATM Agreement”) with H.C. Wainwright & Co., LLC (the “Agent”), as sales agent, pursuant to which the Company may offer and sell shares of common stock, par value $0.001 per share (the “Shares”) up to an aggregate offering price of $7,000,000 from time to time, in an at the market public offering. Sales of the Shares are to be made at prevailing market prices at the time of sale, or as otherwise agreed with the Agent. The Agent will receive a commission from the Company of 3.0% of the gross proceeds of any Shares sold under the ATM Agreement. The Shares sold under the ATM Agreement are offered and sold pursuant to the Company’s shelf registration statement on Form S-3, which was initially filed with the Securities and Exchange Commission (the “SEC”) on March 29, 2022 and declared effective on April 7, 2022, and a prospectus supplement and the accompanying prospectus relating to the At The Market Offering filed with the SEC on May 20, 2022. On August 3, 2022, the Company suspended sales under the ATM Agreement. On March 17, 2023, the Company reactivated the ATM Agreement. During the year ended December 31, 2023, the Company sold 607,241 shares of common stock at an average price of $9.01 per share for aggregate proceeds of approximately $5.5 million, of which approximately $164,000 was paid in the form of commissions to the Agent. There were no sales under the ATM Agreement during the three months ended March 31, 2024. While the Company may attempt additional sales in the future, there can be no assurance that the Company will be successful in acquiring additional funding through these means. Other than the ATM Agreement, the Company currently does not have any commitments to obtain additional funds. Strategic Partnership and Private Placement On March 4, 2024, the Company entered into a License and Distribution Agreement (the “License Agreement”) with Zylox-Tonbridge effective as of the Initial Closing (defined below), pursuant to which the Company will license and distribute certain of the Company’s products (including consumables) in the Greater China region, including mainland China, Hong Kong, Macao, and Taiwan (the “Territory”). Zylox-Tonbridge will lead all regulatory activities for the registration of the Avinger products in the Territory. Avinger will also license its intellectual property and know-how related to Avinger products to Zylox-Tonbridge so that Zylox-Tonbridge can manufacture the localized products in the Territory. Avinger will supply Avinger products to Zylox-Tonbridge until Zylox-Tonbridge’s manufacturing capability has been established and Zylox-Tonbridge has obtained the regulatory approval of the localized products manufactured by Zylox-Tonbridge. All sales of Avinger products locally manufactured by Zylox-Tonbridge with regulatory approval by the regulatory authorities in the Territory and commercialized in the Territory will be royalty bearing to Avinger at a rate from a mid-single to high-single digit percentage depending on the amount of gross revenue as defined in the License Agreement, with certain increases depending on the amount of product gross margin. The License Agreement has an initial term of 20 years, which shall be further automatically extended for additional 20-year terms, subject to certain conditions. The License Agreement may not be terminated by either party, other than for certain uncured material breaches or the other party’s insolvency. In March 2024, the Company received approximately $0.2 million from Zylox-Tonbridge related to inventory consumed for regulatory approval which is recorded as a reduction to research and development expenses in the Condensed Statement of Operations and Comprehensive Loss for the three months ended March 31, 2024 which substantially offset the related expenditures associated with the inventory consumption. In connection with the License Agreement, on March 4, 2024, the Company and Zylox-Tonbridge also entered into a Strategic Cooperation and Framework Agreement in conjunction with the Initial Closing (the “Collaboration Agreement” and, together with the License Agreement, the “Strategic Collaboration”), which provides the opportunity for the Company to access certain Zylox-Tonbridge peripheral vascular products for distribution in the U.S. and Germany. The agreement also provides the option for Avinger to source finished goods inventory from Zylox-Tonbridge following registration of Zylox-Tonbridge’s manufacturing facility with the FDA. Private Placement On March 4, 2024, in connection with the Strategic Collaboration, the Company and Zylox-Tonbridge Medical Limited, a wholly-owned subsidiary of Zylox-Tonbridge (the “Purchaser”), entered into a Securities Purchase Agreement (the “Purchase Agreement”), pursuant to which the Purchaser agreed to purchase, in two tranches, up to an aggregate of $15 million in shares of the Company’s common stock, par value $0.001 per share (the “Common Stock”), and shares of two new series of the Company’s preferred stock (the “Private Placement”). On March 5, 2024, (the “Initial Closing”), the Company issued to the Purchaser 75,327 shares of the Common Stock at a purchase price per share of $3.664 (the “Purchase Price”), and 7,224 shares of a newly authorized Series F convertible preferred stock, par value $0.001 per share (the “Series F Preferred Stock”), at a purchase price per share of $1,000, for an aggregate purchase price of $7.5 million. Each share of Series F Preferred Stock has a stated value of $1,000 and is initially convertible into approximately 273 shares of Common Stock at a conversion price equal to the Purchase Price, subject to the terms of the Certificate of Designation of Preferences, Rights, and Limitations of the Series F Preferred Stock (the “Series F Certificate of Designation”). Upon completion of the following as mutually agreed upon by the Company and the Purchaser: (i) the successful registration and listing under 21 CFR part 807 with the FDA of the Purchaser and one of its designated affiliates to manufacture Avinger’s products, and (ii) the Company achieving an aggregate of $10 million in gross revenue within any four consecutive fiscal quarters after the Initial Closing, excluding any gross revenue achieved by Avinger under the License Agreement discussed above (together, the “Milestones”), the Purchaser will invest an additional $7.5 million (the “Milestone Closing”) to purchase shares of the Company new Series G convertible preferred stock, par value $0.001 per share (the “Series G Preferred Stock”). Each share of Series G Preferred Stock will have a stated value of $1,000 and will be convertible into shares of Common Stock at a conversion price of equal to the lowest of (x) the Purchase Price, (y) the closing price of the Common Stock on the date immediately preceding the Milestone Closing, and (z) the average closing price for the last five trading days preceding the Milestone Closing, provided that the conversion price will be no less than $0.20. The Milestone Closing was determined to be a separate freestanding equity-classified instrument issued together with the common stock and Series F preferred stock, all of which are classified within equity. The Company’s obligations to (i) accept conversion of the shares of Series F Preferred Stock in excess of 19.9% of the Company’s outstanding common stock as of the date of the Purchase Agreement and (ii) issue and sell shares of Series G Preferred Stock upon completion of the Milestones are each subject to receipt of the approval of the Company’s stockholders as is necessary under the rules and regulations of Nasdaq (including, without limitation, Nasdaq Rule 5635(d)). The Company engaged two financial advisors in connection with the Private Placement and agreed to pay them an aggregate cash fee equal to 7% of the gross proceeds to the Company. Additionally, the Company agreed to issue to one financial advisor warrants to purchase an aggregate number of shares of common Stock equal to 2% of the gross proceeds. In connection with the Private Placement, the Company issued the financial advisor warrants (the “Advisor Warrants”) to purchase 40,938 shares of common stock. The cash fee of approximately $0.5 million and warrants with a fair value of approximately $0.1 million are considered financing costs and are recognized as a reduction of the proceeds from the Private Placement. Series A Preferred Stock Exchange On March 5, 2024, the Company entered into a Securities Purchase Agreement (the “A-1 Securities Purchase Agreement”) with CRG to exchange all outstanding shares of Series A preferred stock for 10,000 shares of Series A-1 preferred stock (the “Exchange”). Among other things, the shares of Series A-1 preferred stock: (i) are convertible into an aggregate of approximately 2,729,257 shares of common stock at a conversion price equal to the Purchase Price, (ii) do not accrue or pay dividends payable solely on the Series A-1 preferred stock, (iii) will have no liquidation preference and (iv) will be junior in rank to shares of the Company’s Series E preferred stock, Series F preferred stock and Series G preferred stock. The Exchange resulted in approximately $1.9 million gain included in the net loss applicable to common holders for the three months ended March 31, 2024. CRG Loan Amendment Also on March 5, 2024, the Company entered into Amendment No. 9 to Loan Agreement effective as of the Initial Closing (the “Amendment”) with CRG, which amends the Loan Agreement to, among other things: - extend the interest-only period through December 31, 2026; - provide that interest payable through December 31, 2026 may be payable in kind rather than in cash; and - permit the payment of dividends on the preferred stock issued or issuable to the Purchaser.

Note 2 - Summary of Significant

Note 2 - Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2024
Notes to Financial Statements
Basis of Presentation and Significant Accounting Policies [Text Block]	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed financial statements have been prepared in accordance with United States generally accepted accounting principles (“U.S. GAAP”) and pursuant to the rules and regulations of the SEC. The accompanying unaudited condensed interim financial statements have been prepared on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the Company’s financial information. The results for the three months ended March 31, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024, or for any other interim period or for any future year. The December 31, 2023 condensed balance sheet data has been derived from audited financial statements. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to SEC rules and regulations relating to interim financial statements. These unaudited condensed financial statements and notes should be read in conjunction with the financial statements included in the Company’s Form 10-K for the fiscal year ended December 31, 2023, which was filed with the SEC on March 20, 2024. The Company’s significant accounting policies are more fully described in Note 2 of the Notes to Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023. On September 8, 2023, the Company’s Board of Directors approved an amendment to the Company’s amended and restated certificate of incorporation to effect a 1-for-15 reverse stock split of the Company’s issued and outstanding common stock. The reverse stock split became effective on September 12, 2023. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts and disclosures reported in the financial statements. Management uses significant judgment when making estimates related to its stock-based compensation, accruals related to compensation, the valuation of the common stock warrants, provisions for doubtful accounts receivable and excess and obsolete inventories, clinical trial accruals, and its reserves for sales returns and warranty costs. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions. Concentration of Credit Risk, and Other Risks and Uncertainties Financial instruments that potentially subject the Company to credit risk consist of cash and cash equivalents and accounts receivable to the extent of the amounts recorded on the balance sheets. The Company’s policy is to invest in cash and cash equivalents, consisting of money market funds. These financial instruments are held in Company accounts at one financial institution, First Citizens Bank, which acquired our prior banking partner, Silicon Valley Bank, in March 2023. The counterparties to the agreements relating to the Company’s investments consist of financial institutions of high credit standing. The Company provides for uncollectible amounts when specific credit problems arise. Management’s estimates for uncollectible amounts have been adequate, and management believes that all significant credit risks have been identified at March 31, 2024 and December 31, 2023. On March 10, 2023, the Federal Deposit Insurance Corporation announced that Silicon Valley Bank had been closed by the California Department of Financial Protection and Innovation. While we have regained access to our accounts at Silicon Valley Bank, now a division of First Citizens Bank, and are evaluating our banking relationships, future disruptions of financial institutions where we bank or have credit arrangements, or disruptions of the financial services industry in general, could adversely affect our ability to access our cash and cash equivalents. If we are unable to access our cash and cash equivalents as needed, our financial position and ability to operate our business will be adversely affected. The Company’s accounts receivable are due from a variety of healthcare organizations in the United States and select international markets. The Company provides for uncollectible amounts when specific credit problems arise. Management’s estimates for uncollectible amounts have been adequate, and management believes that all significant credit risks have been identified at March 31, 2024 and December 31, 2023. At March 31, 2024, there was one one one one Product Warranty Costs The Company typically offers a one Three Months Ended March 31, 2024 2023 Beginning balance $ 193 $ 109 Warranty provision 15 19 Usage/Release (26 ) (14 ) Ending balance $ 182 $ 114 Net Loss per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is computed by dividing the net loss applicable to common stockholders by the weighted average number of shares of common stock outstanding during the period, without consideration for potential dilutive common shares. Diluted net loss per share attributable to common stockholders is computed by dividing the net loss applicable to common stockholders by the weighted average number of shares of common stock and dilutive potential shares of common stock outstanding during the period. Any common stock shares subject to repurchase are excluded from the calculations as the continued vesting of such shares is contingent upon the holders’ continued service to the Company. As of March 31, 2024 and 2023, there were no Net loss per share applicable to common stockholders was determined as follows (in thousands, except per share data): Three Months Ended March 31, 2024 2023 Net loss applicable to common stockholders $ (3,674 ) $ (5,862 ) Weighted average common stock outstanding, basic and diluted 1,477 548 Net loss per share attributable to common stockholders, basic and diluted $ (2.49 ) $ (10.70 ) The following potentially dilutive securities outstanding have been excluded from the computations of diluted weighted average shares outstanding because such securities have an anti-dilutive impact due to losses reported: Three Months Ended March 31, 2024 2023 Common stock warrants equivalents 467,343 525,415 Common stock options 15 15 Convertible preferred stock 50,409 60,961 Unvested restricted stock awards 116,916 79,408 634,683 665,799 Segment and Geographical Information The Company operates and manages its business as one Fair Value Measurements As of March 31, 2024 and December 31, 2023, cash equivalents were all categorized as Level 1 and consisted of money market funds. As of March 31, 2024 and December 31, 2023, there were no financial assets and liabilities categorized as Level 2 or 3. There were no transfers between fair value hierarchy levels during the three months ended March 31, 2024. Recent Accounting Pronouncements Recent accounting standards adopted In August 2020, the FASB issued ASU No. 2020-06, Debt Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging Contracts in Entity s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity s Own Equity In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280) Improvements to Reportable Segment Disclosures Recent accounting standards not yet adopted In December 2023, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures

Note 3 - Inventories

Note 3 - Inventories	3 Months Ended
	Mar. 31, 2024
Notes to Financial Statements
Inventory Disclosure [Text Block]	3. Inventories Inventories consisted of the following (in thousands): March 31, December 31, 2024 2023 Raw materials $ 2,741 $ 3,203 Work-in-process 130 25 Finished products 1,691 2,070 Total inventories $ 4,562 $ 5,298

Note 4 - Borrowings

Note 4 - Borrowings	3 Months Ended
	Mar. 31, 2024
Notes to Financial Statements
Debt Disclosure [Text Block]	4. Borrowings CRG On September 22, 2015, the Company entered into a Term Loan Agreement, as amended (the “Loan Agreement”) with CRG under which, subject to certain conditions, the Company had the right to borrow up to $50 million in principal amount from CRG on or before the end of the twenty-fourth (24 th On February 14, 2018, the Company and CRG further amended the Loan Agreement concurrent with the conversion of $38 million of the principal amount of the senior secured term loan (plus $3.8 million in back-end fees and prepayment premium applicable thereto) into a newly authorized Series A convertible preferred stock. On August 2, 2023, the Company and CRG entered into a Securities Purchase Agreement (“SPA”) pursuant to which the Company issued 1,920 shares of a newly authorized Series E convertible preferred stock (“Series E Preferred Stock”) in exchange for CRG surrendering for cancellation $1.92 million of outstanding principal and accrued interest of the senior secured term loan under the Loan Agreement. Each share of Series E preferred stock has a stated value of $1,000 per share and is convertible into 93 shares of the Company’s common stock at a conversion price of $10.725 per share, provided that the shares of Series E preferred stock cannot be converted into common stock to the extent the applicable holder would beneficially own in excess of 19.99% of the Company’s outstanding voting power, unless approved by the Company's stockholders in accordance with Nasdaq Listing Rule 5635(b). The Company has entered into several amendments to the Loan Agreement (the “Amendments”) with CRG since September 2015. The Amendments, among other things: (1) extended the interest-only period through December 31, 2026; (2) extended the period during which the Company may elect to pay a portion of interest in payment-in-kind (“PIK”), interest payments through December 31, 2026 so long as no Default (as defined in the Loan Agreement) has occurred and is continuing; (3) permitted the Company to make the entire interest payments in PIK interest payments through December 31, 2026 so long as no Default has occurred and is continuing; (4) extended the Stated Maturity Date (as defined in the Loan Agreement) to December 31, 2025; (5) reduced the minimum liquidity covenant to $3.5 million at all times; (6) eliminated the minimum revenue covenants for all years (7) changed the date under the on-going stand-alone representation regarding no “Material Adverse Change” to December 31, 2020; (8) amended the on-going stand-alone representation and stand-alone Event of Default (as defined in the Loan Agreement) regarding Material Adverse Change such that any adverse change in or effect upon the revenue of the Company and its subsidiaries due to the outbreak of COVID-19 will not constitute a Material Adverse Change; (9) provided CRG with board observer rights and (10) provide that the board observer may be appointed or removed by written notice from the Majority Lenders (as defined in the Loan Agreement). On January 26, 2024, the Company entered into Amendment No. 8 to the Loan Agreement with CRG, which reduces the minimum liquidity requirement of the Loan Agreement from $3.5 million to $1.0 million until April 1, 2024. Thereafter, the Company will be subject to the minimum liquidity requirement of $3.5 million. On March 5, 2024, the Company entered into Amendment No. 9 to the Loan Agreement with CRG, which (1) extended the interest-only period through December 31, 2026; (2) extended the period during which the Company may elect to pay a portion of interest in PIK interest payments through December 31, 2026 so long as no Default (as defined in the Loan Agreement) has occurred and is continuing; (3) permitted the Company to make the entire interest payments in PIK interest payments through December 31, 2026 so long as no Default has occurred and is continuing; and (4) permit the payment of dividends on the preferred stock issued or issuable to the Purchaser. The Company assessed Amendments Nos. 8 and 9 to the Loan Agreement entered into during the quarter ended March 31, 2024 and determined that these represented loan modifications. As such, the unamortized portion of previous issuance costs incurred will be amortized over the modified term, and costs incurred with third parties was expensed as incurred. Under the amended Loan Agreement, no cash payments for either principal or interest are required until the first quarter of 2027. The interest will be accrued and included in the debt balance based (to the extent not paid) on principal amounts outstanding at the beginning of the quarter at an interest rate of 12.5%. Beginning in the first quarter of 2027, the Company will be required to make quarterly principal payments (in addition to the interest) of $2.4 million with total principal payments of $9.4 million in 2027 and $9.4 million in 2028. The maturity date of the Loan (as defined in the Loan Agreement) is December 31, 2028. The Company may voluntarily prepay the borrowings in full, with a prepayment premium beginning at 5.0% and declining by 1.0% annually thereafter, with no premium being payable if prepayment occurs after seven and half years of the loan. There is currently no prepayment premium payable. Each tranche of borrowing required the payment, on the borrowing date, of a financing fee equal to 1.5% of the borrowed loan principal, which is recorded as a discount to the debt. In addition, a facility fee equal to 15.0% of the amounts borrowed plus any PIK is to be payable at the end of the term or when the borrowings are repaid in full. A long-term liability is being accreted using the effective interest method for the facility fee over the term of the Loan Agreement with a corresponding discount to the debt. The borrowings are collateralized by a security interest in substantially all of the Company’s assets. The Loan Agreement requires that the Company adheres to certain affirmative and negative covenants, including financial reporting requirements, certain minimum financial covenants for pre-specified liquidity and a prohibition against the incurrence of indebtedness, or creation of additional liens, other than as specifically permitted by the terms of the Loan Agreement. In particular, the covenants of the amended Loan Agreement included a covenant that the Company maintain a minimum of $3.5 million of cash and certain cash equivalents. The minimum liquidity requirement was temporarily reduced to $1.0 million until April 1, 2024. In addition, the Loan Agreement prohibits the payment of cash dividends on the Company’s capital stock and also places restrictions on mergers, sales of assets, investments, incurrence of liens, incurrence of indebtedness and transactions with affiliates. CRG may accelerate the payment terms of the Loan Agreement upon the occurrence of certain “Events of Default” set forth therein, which include the failure of the Company to make timely payments of amounts due under the Loan Agreement, the failure of the Company to adhere to the covenants set forth in the Loan Agreement, the insolvency of the Company or upon the occurrence of a “Material Adverse Change” thereunder. As of March 31, 2024, the Company was in compliance with all applicable covenants under the Loan Agreement. As of March 31, 2024, principal, final facility fee and PIK payments under the Loan Agreement, as amended, were as follows (in thousands): Year Ending December 31, 2024 (remaining nine months of the year) $ — 2025 — 2026 — 2027 11,378 2028 13,017 Total 24,395 Less: Amount of PIK additions and final facility fee to be incurred subsequent to March 31, 2024 (9,494 ) Less: Amount representing debt issuance costs (150 ) Borrowings, current portion, as of March 31, 2024 $ 14,751 In connection with drawdowns under the Loan Agreement, the Company recorded aggregate debt discounts of $1.3 million as contra-debt. The debt discounts are being amortized as non-cash interest expense using the effective interest method over the term of the Loan Agreement. As of March 31, 2024 and December 31, 2023, the balance of the aggregate debt discount was approximately $150,000 and $166,000, respectively. The Company’s interest expense associated with the amortization of debt discount was approximately $16,000 and $21,000 during the three months ended March 31, 2024 and 2023, respectively. For the three months ended March 31, 2024 and 2023, the Company incurred total interest expense of approximately $458,000 and $507,000, respectively. While, as of the date hereof, CRG has not purported that an Event of Default has resulted due to a Material Adverse Change (as those terms defined in the Loan Agreement), due to the substantial doubt about the Company’s ability to continue operating as a going concern, the entire outstanding amount of borrowings under the Loan Agreement and associated aggregate debt discount at March 31, 2024 and December 31, 2023 were classified as current in these financial statements.

Note 5 - Leases

Note 5 - Leases	3 Months Ended
	Mar. 31, 2024
Notes to Financial Statements
Lessee, Operating Leases [Text Block]	5. Leases The Company’s operating lease obligations primarily consist of leased office, laboratory, and manufacturing space under a non-cancelable operating lease. In addition to the minimum future lease commitments presented below, the lease requires the Company to pay property taxes, insurance, maintenance, and repair costs. The most recent amendment also provides an optional one-year extension of the lease following the end of the current term on November 30, 2025, which was not included in the assessment of the lease term as it is not reasonably certain the Company will elect to exercise this option. Rent expense is recognized using the straight-line method over the term of the lease. The current lease was to expire on November 30, 2024. On March 6, 2024, the Company entered into an amendment to the lease which extended the lease term for a period of one year, subsequent to the original expiration. As amended, the lease will expire on November 30, 2025. Under the terms of the amendment, the Company will be obligated to pay an additional $1.3 million in base rent payments through November 2025, beginning on December 1, 2024. In total, the Company is obligated to pay approximately $7.1 million in base rent payments through November 2025, which began on December 1, 2019. The weighted average remaining lease term as of March 31, 2024 is 1.7 years. In connection with the amendment the Company adjusted its right-of-use asset and lease liability to $2.2 million. As of the date of the amendment, the operating lease was included on the balance sheet at the present value of the future base payments discounted at a 6.5% discount rate using the rate of interest that the Company would have to pay to borrow on a collateralized basis over a similar term and amount equal to the lease payments in a similar economic environment as the lease do provide an implicit rate. The Company’s operating lease expense, excluding variable maintenance fees and other expenses on a monthly basis, was approximately $105,000. Rent expense for the three months ended March 31, 2024 and 2023 was approximately$315,000 and $314,000, respectively. The Company’s variable expenses for the three months ended March 31, 2024 and 2023 were approximately $90,000 and $65,000, respectively. Operating right-of-use asset amortization for the three months ended March 31, 2024 and 2023 was approximately $292,000 and $280,000, respectively. Due to payments being made in excess of operating lease expense recognized, the Company recorded approximately $9,000 and $13,000 as prepaid rent included in other assets on the condensed balance sheet as of March 31, 2024 and December 31, 2023, respectively. The following table presents the future operating lease payments and leasehold liability included on the balance sheet related to the Company’s operating lease as of March 31, 2023 (in thousands): Year Ending December 31, 2024 (remaining nine months of the year) $ 934 2025 1,166 Total 2,100 Less: Imputed interest (109 ) Leasehold liability as of March 31, 2024 $ 1,991 The following table shows ROU assets and lease liabilities, and the associated financial statement line items, as of March 31, 2024 and December 31, 2023 (in thousands): Financial Statement Line March 31, December 31, Lease-Related Assets and Liabilities Items 2024 2023 Right of use assets: Operating lease Right of use asset $ 1,991 $ 1,102 Total right of use assets $ 1,991 $ 1,102 Lease liabilities: Operating lease Leasehold liability, current portion $ 1,156 $ 1,102 Leasehold liability, long-term portion 835 — Total lease liabilities $ 1,991 $ 1,102

Note 6 - Commitments and Contin

Note 6 - Commitments and Contingencies	3 Months Ended
	Mar. 31, 2024
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	6. Commitments and Contingencies Purchase Obligations Purchase obligations consist of agreements to purchase goods and services entered into in the ordinary course of business. The Company had non-cancelable commitments to suppliers for purchases totaling approximately $0.4 million as of March 31, 2024. The majority of this amount is related to commitments to purchase inventory components and services related to the manufacturing of inventory. Legal Proceedings The Company is not currently involved in any pending legal proceedings that it believes could have a material adverse effect on our financial condition, results of operations or cash flows. From time to time, the Company may be involved in legal proceedings or investigations, which could harm our reputation, business and financial condition and divert the attention of our management from the operation of our business.

Note 7 - Stockholders' Equity

Note 7 - Stockholders' Equity	3 Months Ended
	Mar. 31, 2024
Notes to Financial Statements
Equity [Text Block]	7. Stockholders Equity Convertible Preferred Stock As of March 31, 2024 and December 31, 2023, the Company’s certificate of incorporation, as amended and restated, authorizes the Company to issue up to 5,000,000 shares of convertible preferred stock with $0.001 par value per share. As of March 31, 2024 and December 31, 2023, 19,229 and 62,881 shares, respectively, were issued and outstanding. Series A Preferred Stock Exchange On March 5, 2024, the Company entered into the A-1 Securities Purchase Agreement with CRG to exchange all 60,876 outstanding shares of Series A preferred stock for 10,000 shares of Series A-1 preferred stock. Consequently, there are no shares of Series A preferred stock outstanding as of March 31, 2024. The exchange was accounted for as a capital transaction constituting an extinguishment of the Series A preferred stock through the issuance of Series A-1 preferred stock with no net impact to stockholders’ deficit. At the time of the exchange, the Series A preferred stock had approximately $1.9 million excess fair value in comparison to the Series A-1. The difference in fair value is treated as an adjustment to net loss applicable to common stockholders for the purpose of calculating earnings per share, see Note 2 Series A-1 Convertible Preferred Stock Each share of Series A-1 preferred stock has a stated value of $1,000 per share and is convertible into 273 shares of the Company’s common stock at $3.664 per share. The Series A-1 preferred stock is convertible into a total of 2,729,257 shares of common stock subject to certain limitations contained in the A-1 Securities Purchase Agreement. Shares of Series A-1 preferred stock cannot be converted into common stock to the extent the applicable holder would beneficially own in excess of 19.99% of the Company’s outstanding voting power, unless approved by the Company's stockholders in accordance with Nasdaq Listing Rule 5635(b).The Series A-1 preferred stock has no liquidation preference, no voting rights and ranks junior to shares of the Company’s Series E Preferred Stock, Series F Preferred Stock and Series G Preferred Stock in terms of repayment and certain other rights. The Series A-1 preferred stock is immediately convertible at the option of the holder, has no stated maturity, and does not pay regularly stated dividends or interest. As of March 31, 2024, 10,000 shares of Series A-1 preferred stock were outstanding. Series B Convertible Preferred Stock The Series B preferred stock has a liquidation preference of $0.001 per share, full ratchet price based anti-dilution protection, has no voting rights and is subject to certain ownership limitations. The Series B preferred stock is immediately convertible at the option of the holder, has no stated maturity, and does not pay regularly stated dividends or interest. As of March 31, 2024 and December 31, 2023, 85 shares of Series B preferred stock remained outstanding, which are currently convertible into shares of the Company’s common stock at $3.664 per share. Series E Convertible Preferred Stock Each share of Series E preferred stock has a stated value of $1,000 per share and is convertible into 93 shares of the Company’s common stock at a conversion price of $10.725 per share. The Series E preferred stock is convertible into a total of 178,560 shares of common stock subject to certain limitations contained in the Series E Purchase Agreement. Shares of Series E preferred stock cannot be converted into common stock to the extent the applicable holder would beneficially own in excess of 19.99% of the Company’s outstanding voting power, unless approved by the Company's stockholders in accordance with Nasdaq Listing Rule 5635(b). The holders of Series E preferred stock are entitled to receive annual accruing dividends at a rate of 8%, payable in additional shares of Series E preferred stock or cash, at the Company’s option. The shares of Series E preferred stock have full voting rights, on an as-converted basis, subject to certain limitations. The Series E preferred stock rank senior to all other classes and series of the Company’s equity in terms of repayment and certain other rights. The Series E preferred stock accrued additional dividends of less than $0.1 million during the three months ended March 31, 2024, which were recognized as a reduction to additional paid-in capital in the statement of stockholders’ deficit. As of March 31, 2024 and December 31, 2023, 1,920 shares of Series E preferred stock were outstanding. Series F Convertible Preferred Stock On March 4, 2024, in connection with the Purchase Agreement (see Note 1 Common Stock As of March 31, 2024, the Company’s certificate of incorporation, as amended and restated, authorizes the Company to issue up to 100,000,000 shares of common stock with $0.001 par value per share, of which 1,586,434 shares were issued and outstanding. March 2024 Offering On March 5, 2024, in connection with the Purchase Agreement (see Note 1 Common Stock Warrants As of March 31, 2024 and December 31, 2023, warrants and preferred investment options to purchase an aggregate of 497,034 and 456,096 shares of common stock were outstanding, respectively, all of which were classified within the equity section of the respective balance sheets. As of March 31, 2024, the Company had outstanding warrants to purchase common stock as follows: Total Outstanding and Exercisable Underlying Shares of Common Stock Exercise Price per Share Expiration Date Series 1 Warrants issued in the February 2018 Series B financing 8,979,000 2,993 $ 6,000.00 February 2025 Series 2 Warrants issued in the February 2018 Series B financing 8,709,500 2,903 $ 6,000.00 February 2025 Placement agent warrants issued in the January 2022 financing 1,330,000 4,433 $ 150.00 January 2027 Warrants issued in the January 2022 financing 16,150,000 53,833 $ 144.00 July 2027 Series A Preferred Investment Options issued in August 2022 financing 2,853,883 190,259 $ 22.53 February 2028 Series B Preferred Investment Options issued in August 2022 financing 2,853,883 190,259 $ 22.53 August 2024 Placement agent Preferred Investment Options issued in the August 2022 financing 171,233 11,416 $ 32.85 August 2027 Advisor Warrants issued in the March 2024 financing 40,938 40,938 $ 3.664 March 2029 Total as of March 31, 2024 41,088,437 497,034 As of December 31, 2023, the Company had outstanding warrants to purchase common stock as follows: Total Outstanding and Exercisable Underlying Shares of Common Stock Exercise Price per Share Expiration Date Series 1 Warrants issued in the February 2018 Series B financing 8,979,000 2,993 $ 6,000.00 February 2025 Series 2 Warrants issued in the February 2018 Series B financing 8,709,500 2,903 $ 6,000.00 February 2025 Placement agent warrants issued in the January 2022 financing 1,330,000 4,433 $ 150.00 January 2027 Warrants issued in the January 2022 financing 16,150,000 53,833 $ 144.00 July 2027 Series A Preferred Investment Options issued in August 2022 financing 2,853,883 190,259 $ 22.53 February 2028 Series B Preferred Investment Options issued in August 2022 financing 2,853,883 190,259 $ 22.53 August 2024 Placement agent Preferred Investment Options issued in the August 2022 financing 171,233 11,416 $ 32.85 August 2027 Total as of December 31, 2023 41,047,499 456,096 March 2024 Private Placement On March 7, 2024, in connection with the closing of the Strategic Partnership and Private Placement, the Company issued warrants to financial advisors to purchase up to an aggregate of 40,938 shares of the Company’s common stock (the “Advisor Warrants”) at an exercise price of $3.664 per share which were immediately exercisable. The Advisor Warrants will expire five The exercise price and the number of shares of common stock issuable upon exercise of each Advisor Warrants are subject to appropriate adjustments in the event of certain stock dividends and distributions, stock splits, stock combinations, reclassifications or similar events affecting the common stock. In addition, in certain circumstances, upon a fundamental transaction, a holder of Advisor Warrants will be entitled to receive, upon exercise, the kind and amount of securities, cash or other property that such holder would have received had they exercised the Advisor Warrants prior to the fundamental transaction. The Advisor Warrants can be exercised at the option of the holders at any time after they become exercisable provided that shares cannot be exercised into common stock if the applicable holder would beneficially own in excess of 4.99% of the Company’s outstanding common stock immediately after giving effect to the exercise. A holder of the Advisor Warrants may, upon notice to the Company, increase or decrease such beneficial ownership limitation, but not in excess of 9.99%.

Note 8 - Stock-based Compensati

Note 8 - Stock-based Compensation	3 Months Ended
	Mar. 31, 2024
Notes to Financial Statements
Share-Based Payment Arrangement [Text Block]	8. Stock-Based Compensation Stock Plans In January 2015, the Board of Directors adopted and the Company’s stockholders approved the 2015 Equity Incentive Plan (“2015 Plan”). On December 22, 2023, the Company’s stockholders approved an additional 300,000 shares of common stock for issuance under the 2015 Plan, which was later registered in an S-8 registration statement filed on January 10, 2024. The 2015 Plan provides for the grant of incentive stock options (“ISOs”) to employees and for the grant of non-statutory stock options (“NSOs”), restricted stock, restricted stock awards (“RSAs”), restricted stock units (“RSUs”), stock appreciation rights, performance units and performance shares to employees, directors and consultants. As of March 31, 2024, 68,109 shares were available for grant under the 2015 Plan. The Company’s RSUs and RSAs generally vest annually over two years in equal increments. RSAs and RSUs largely contain the same contractual terms except RSAs have the ability to vote along with common holders as an RSA is considered an outstanding security at the time of grant, subject to certain vesting and other restrictions. The Company measures the fair value of RSAs using the closing stock price of a share of the Company’s common stock on the grant date and is recognized as expense on a straight-line basis over the vesting period of the award. A summary of all RSA activity is presented below: Number of Shares Weighted Average Grant Date Fair Value Weighted Average Remaining Contractual Term Awards outstanding at December 31, 2023 90,190 $ 18.45 1.04 Awarded 394,105 $ 2.75 — Released (368,503 ) $ 4.89 — Forfeited — $ — — Awards outstanding at March 31, 2024 115,792 $ 8.16 0.8 As of March 31, 2024, there was approximately $0.8 million of remaining unamortized stock-based compensation expense associated with RSAs, which will be expensed over a weighted average remaining service period of approximately 0.8 years. The outstanding non-vested and expected to vest RSAs at March 31, 2024 have an aggregate fair value of approximately $0.4 million. The Company used the closing market price of $3.10 per share at March 28, 2024, to determine the aggregate fair value for the RSAs outstanding at that date. For the three months ended March 31, 2024 and 2023, the fair value of RSAs vested was approximately $1.0 million and less than $0.1 million, respectively. For the three months ended March 31, 2024 and 2023, stock-based compensation expense recognized associated with the vesting of RSAs was $1.1 million and $0.2 million, respectively. All awards outstanding as of March 31, 2024 are RSAs. Total noncash stock-based compensation expense relating to the Company’s RSAs recognized, before taxes, during the three months ended March 31, 2024 and 2023, is as follows (in thousands): Three Months Ended March 31, 2024 2023 Cost of revenues $ 158 $ 28 Research and development expenses 314 83 Selling, general and administrative expenses 624 134 $ 1,096 $ 245

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024
Insider Trading Arr Line Items
Material Terms of Trading Arrangement [Text Block]	ITEM 5. OTHER INFORMATION 10b5-1 Trading Plans During the first quarter of 2024, none
Rule 10b5-1 Arrangement Adopted [Flag]	false
Non-Rule 10b5-1 Arrangement Adopted [Flag]	false
Rule 10b5-1 Arrangement Terminated [Flag]	false
Non-Rule 10b5-1 Arrangement Terminated [Flag]	false

Significant Accounting Policies

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation The accompanying unaudited condensed financial statements have been prepared in accordance with United States generally accepted accounting principles (“U.S. GAAP”) and pursuant to the rules and regulations of the SEC. The accompanying unaudited condensed interim financial statements have been prepared on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the Company’s financial information. The results for the three months ended March 31, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024, or for any other interim period or for any future year. The December 31, 2023 condensed balance sheet data has been derived from audited financial statements. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to SEC rules and regulations relating to interim financial statements. These unaudited condensed financial statements and notes should be read in conjunction with the financial statements included in the Company’s Form 10-K for the fiscal year ended December 31, 2023, which was filed with the SEC on March 20, 2024. The Company’s significant accounting policies are more fully described in Note 2 of the Notes to Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023. On September 8, 2023, the Company’s Board of Directors approved an amendment to the Company’s amended and restated certificate of incorporation to effect a 1-for-15 reverse stock split of the Company’s issued and outstanding common stock. The reverse stock split became effective on September 12, 2023.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts and disclosures reported in the financial statements. Management uses significant judgment when making estimates related to its stock-based compensation, accruals related to compensation, the valuation of the common stock warrants, provisions for doubtful accounts receivable and excess and obsolete inventories, clinical trial accruals, and its reserves for sales returns and warranty costs. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions.
Concentration of Credit Risk and Other Risks and Uncertainties [Policy Text Block]	Concentration of Credit Risk, and Other Risks and Uncertainties Financial instruments that potentially subject the Company to credit risk consist of cash and cash equivalents and accounts receivable to the extent of the amounts recorded on the balance sheets. The Company’s policy is to invest in cash and cash equivalents, consisting of money market funds. These financial instruments are held in Company accounts at one financial institution, First Citizens Bank, which acquired our prior banking partner, Silicon Valley Bank, in March 2023. The counterparties to the agreements relating to the Company’s investments consist of financial institutions of high credit standing. The Company provides for uncollectible amounts when specific credit problems arise. Management’s estimates for uncollectible amounts have been adequate, and management believes that all significant credit risks have been identified at March 31, 2024 and December 31, 2023. On March 10, 2023, the Federal Deposit Insurance Corporation announced that Silicon Valley Bank had been closed by the California Department of Financial Protection and Innovation. While we have regained access to our accounts at Silicon Valley Bank, now a division of First Citizens Bank, and are evaluating our banking relationships, future disruptions of financial institutions where we bank or have credit arrangements, or disruptions of the financial services industry in general, could adversely affect our ability to access our cash and cash equivalents. If we are unable to access our cash and cash equivalents as needed, our financial position and ability to operate our business will be adversely affected. The Company’s accounts receivable are due from a variety of healthcare organizations in the United States and select international markets. The Company provides for uncollectible amounts when specific credit problems arise. Management’s estimates for uncollectible amounts have been adequate, and management believes that all significant credit risks have been identified at March 31, 2024 and December 31, 2023. At March 31, 2024, there was one one one one
Standard Product Warranty, Policy [Policy Text Block]	Product Warranty Costs The Company typically offers a one Three Months Ended March 31, 2024 2023 Beginning balance $ 193 $ 109 Warranty provision 15 19 Usage/Release (26 ) (14 ) Ending balance $ 182 $ 114
Earnings Per Share, Policy [Policy Text Block]	Net Loss per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is computed by dividing the net loss applicable to common stockholders by the weighted average number of shares of common stock outstanding during the period, without consideration for potential dilutive common shares. Diluted net loss per share attributable to common stockholders is computed by dividing the net loss applicable to common stockholders by the weighted average number of shares of common stock and dilutive potential shares of common stock outstanding during the period. Any common stock shares subject to repurchase are excluded from the calculations as the continued vesting of such shares is contingent upon the holders’ continued service to the Company. As of March 31, 2024 and 2023, there were no Net loss per share applicable to common stockholders was determined as follows (in thousands, except per share data): Three Months Ended March 31, 2024 2023 Net loss applicable to common stockholders $ (3,674 ) $ (5,862 ) Weighted average common stock outstanding, basic and diluted 1,477 548 Net loss per share attributable to common stockholders, basic and diluted $ (2.49 ) $ (10.70 ) The following potentially dilutive securities outstanding have been excluded from the computations of diluted weighted average shares outstanding because such securities have an anti-dilutive impact due to losses reported: Three Months Ended March 31, 2024 2023 Common stock warrants equivalents 467,343 525,415 Common stock options 15 15 Convertible preferred stock 50,409 60,961 Unvested restricted stock awards 116,916 79,408 634,683 665,799
Segment Reporting, Policy [Policy Text Block]	Segment and Geographical Information The Company operates and manages its business as one
Fair Value Measurement, Policy [Policy Text Block]	Fair Value Measurements As of March 31, 2024 and December 31, 2023, cash equivalents were all categorized as Level 1 and consisted of money market funds. As of March 31, 2024 and December 31, 2023, there were no financial assets and liabilities categorized as Level 2 or 3. There were no transfers between fair value hierarchy levels during the three months ended March 31, 2024.
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements Recent accounting standards adopted In August 2020, the FASB issued ASU No. 2020-06, Debt Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging Contracts in Entity s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity s Own Equity In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280) Improvements to Reportable Segment Disclosures Recent accounting standards not yet adopted In December 2023, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures

Note 2 - Summary of Significa_2

Note 2 - Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2024
Notes Tables
Schedule of Product Warranty Liability [Table Text Block]	Three Months Ended March 31, 2024 2023 Beginning balance $ 193 $ 109 Warranty provision 15 19 Usage/Release (26 ) (14 ) Ending balance $ 182 $ 114
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Three Months Ended March 31, 2024 2023 Net loss applicable to common stockholders $ (3,674 ) $ (5,862 ) Weighted average common stock outstanding, basic and diluted 1,477 548 Net loss per share attributable to common stockholders, basic and diluted $ (2.49 ) $ (10.70 )
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	Three Months Ended March 31, 2024 2023 Common stock warrants equivalents 467,343 525,415 Common stock options 15 15 Convertible preferred stock 50,409 60,961 Unvested restricted stock awards 116,916 79,408 634,683 665,799

Note 3 - Inventories (Tables)

Note 3 - Inventories (Tables)	3 Months Ended
	Mar. 31, 2024
Notes Tables
Schedule of Inventory, Current [Table Text Block]	March 31, December 31, 2024 2023 Raw materials $ 2,741 $ 3,203 Work-in-process 130 25 Finished products 1,691 2,070 Total inventories $ 4,562 $ 5,298

Note 4 - Borrowings (Tables)

Note 4 - Borrowings (Tables)	3 Months Ended
	Mar. 31, 2024
Notes Tables
Schedule of Debt [Table Text Block]	Year Ending December 31, 2024 (remaining nine months of the year) $ — 2025 — 2026 — 2027 11,378 2028 13,017 Total 24,395 Less: Amount of PIK additions and final facility fee to be incurred subsequent to March 31, 2024 (9,494 ) Less: Amount representing debt issuance costs (150 ) Borrowings, current portion, as of March 31, 2024 $ 14,751

Note 5 - Leases (Tables)

Note 5 - Leases (Tables)	3 Months Ended
	Mar. 31, 2024
Notes Tables
Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block]	Year Ending December 31, 2024 (remaining nine months of the year) $ 934 2025 1,166 Total 2,100 Less: Imputed interest (109 ) Leasehold liability as of March 31, 2024 $ 1,991
Right of Use Asset and Liabilities [Table Text Block]	Financial Statement Line March 31, December 31, Lease-Related Assets and Liabilities Items 2024 2023 Right of use assets: Operating lease Right of use asset $ 1,991 $ 1,102 Total right of use assets $ 1,991 $ 1,102 Lease liabilities: Operating lease Leasehold liability, current portion $ 1,156 $ 1,102 Leasehold liability, long-term portion 835 — Total lease liabilities $ 1,991 $ 1,102

Note 7 - Stockholders' Equity (

Note 7 - Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2024
Notes Tables
Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]	Total Outstanding and Exercisable Underlying Shares of Common Stock Exercise Price per Share Expiration Date Series 1 Warrants issued in the February 2018 Series B financing 8,979,000 2,993 $ 6,000.00 February 2025 Series 2 Warrants issued in the February 2018 Series B financing 8,709,500 2,903 $ 6,000.00 February 2025 Placement agent warrants issued in the January 2022 financing 1,330,000 4,433 $ 150.00 January 2027 Warrants issued in the January 2022 financing 16,150,000 53,833 $ 144.00 July 2027 Series A Preferred Investment Options issued in August 2022 financing 2,853,883 190,259 $ 22.53 February 2028 Series B Preferred Investment Options issued in August 2022 financing 2,853,883 190,259 $ 22.53 August 2024 Placement agent Preferred Investment Options issued in the August 2022 financing 171,233 11,416 $ 32.85 August 2027 Advisor Warrants issued in the March 2024 financing 40,938 40,938 $ 3.664 March 2029 Total as of March 31, 2024 41,088,437 497,034 Total Outstanding and Exercisable Underlying Shares of Common Stock Exercise Price per Share Expiration Date Series 1 Warrants issued in the February 2018 Series B financing 8,979,000 2,993 $ 6,000.00 February 2025 Series 2 Warrants issued in the February 2018 Series B financing 8,709,500 2,903 $ 6,000.00 February 2025 Placement agent warrants issued in the January 2022 financing 1,330,000 4,433 $ 150.00 January 2027 Warrants issued in the January 2022 financing 16,150,000 53,833 $ 144.00 July 2027 Series A Preferred Investment Options issued in August 2022 financing 2,853,883 190,259 $ 22.53 February 2028 Series B Preferred Investment Options issued in August 2022 financing 2,853,883 190,259 $ 22.53 August 2024 Placement agent Preferred Investment Options issued in the August 2022 financing 171,233 11,416 $ 32.85 August 2027 Total as of December 31, 2023 41,047,499 456,096

Note 8 - Stock-based Compensa_2

Note 8 - Stock-based Compensation (Tables)	3 Months Ended
	Mar. 31, 2024
Notes Tables
Share-Based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block]	Number of Shares Weighted Average Grant Date Fair Value Weighted Average Remaining Contractual Term Awards outstanding at December 31, 2023 90,190 $ 18.45 1.04 Awarded 394,105 $ 2.75 — Released (368,503 ) $ 4.89 — Forfeited — $ — — Awards outstanding at March 31, 2024 115,792 $ 8.16 0.8
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]	Three Months Ended March 31, 2024 2023 Cost of revenues $ 158 $ 28 Research and development expenses 314 83 Selling, general and administrative expenses 624 134 $ 1,096 $ 245

Note 1 - Organization (Details

Note 1 - Organization (Details Textual)			1 Months Ended	3 Months Ended		9 Months Ended
	Mar. 05, 2024 USD ($) shares	Mar. 04, 2024 USD ($) $ / shares shares	Aug. 31, 2022 USD ($)	Mar. 31, 2024 USD ($) $ / shares shares	Mar. 31, 2023 USD ($) shares	Sep. 30, 2023 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 23, 2023 shares	Dec. 31, 2022 $ / shares	May 20, 2022 USD ($) $ / shares
Proceeds from Issuance or Sale of Equity		$ 7,500,000
Retained Earnings (Accumulated Deficit)				$ (426,213,000)		$ (426,200,000)	$ (420,696,000)
Cash and Cash Equivalents, at Carrying Value				$ 7,174,000		$ 7,200,000	$ 5,275,000
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares		$ 0.001		$ 0.001		$ 0.001			$ 0.001
Agreement to Purchase Common Stock, Maximum Amount		$ 15,000,000
Preferred Stock, Par or Stated Value Per Share | $ / shares				$ 0.001			$ 0.001		$ 0.001
Milestone Payment, Additional Authorized Amount		$ 7,500,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares		40,938		497,034			456,096	456,096
Fair Value Adjustment of Warrants		$ 500,000
Gain (Loss) On Convertible Preferred Stock Converted to Other Securities		$ 100,000		$ 1,908,000	$ 0
Securities Purchase Agreement, Number of Shares to Convert | shares	10,000
Loan Agreement [Member]
Debt Instrument, Financing Fee Percentage		2%
Loan Agreement [Member]
Debt Instrument, Financing Fee Percentage		7%
Series F Preferred Stock [Member]
Stock Issued During Period, Shares, New Issues | shares		7,224
Shares Issued, Price Per Share | $ / shares		$ 1,000
Preferred Stock, Par or Stated Value Per Share | $ / shares		0.001
Preferred Stock, Stated Value | $ / shares		$ 1,000
Preferred Stock, Convertible, Conversion Ratio		273
Series G Preferred Stock [Member]
Preferred Stock, Stated Value | $ / shares		$ 1,000
Preferred Stock, Par Value | $ / shares		$ 0.001
Series A-1 Preferred Stock [Member]
Preferred Stock, Stated Value | $ / shares				$ 1,000
Preferred Stock, Convertible, Conversion Ratio				273
Securities Purchase Agreement, Number of Shares to Convert | shares				10,000
Preferred Stock, Convertible, Shares Issuable | shares	2,729,257			2,729,257
Common Stock [Member]
Stock Issued During Period, Shares, New Issues | shares		75,327			794
Shares Issued, Price Per Share | $ / shares		$ 3.664		$ 3.664
License and Distribution Agreement [Member]
License Agreement, Term		20 years
Securities Purchase Agreement [Member]
Proceeds from Issuance or Sale of Equity	$ 7,500,000
August 2022 Public Offering [Member]
Proceeds from Issuance or Sale of Equity, Net			$ 6,500,000
Common Stock in June, 2022 [Member]
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares										$ 0.001
Share Offering Agreement, Aggregate Offering										$ 7,000,000
Commission Percentage										3%
The Market Offering Agreement (the “ATM Agreement”) [Member]
Proceeds from Issuance or Sale of Equity						$ 5,500,000
Stock Issued During Period, Shares, New Issues | shares						607,241
Stock Issued During Period, Average Price Per Share | $ / shares						$ 9.01
Payments of Stock Issuance Costs						$ 164,000

Note 2 - Summary of Significa_3

Note 2 - Summary of Significant Accounting Policies (Details Textual) shares in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024 shares	Mar. 31, 2023 shares	Dec. 31, 2023
Warranty Period (Year)	1 year
Weighted Average Number of Shares, Common Stock Subject to Repurchase or Cancellation	0	0
Number of Reportable Segments	1
Customer Concentration Risk [Member] | Accounts Receivable [Member]
Number of Major Customers	1		1
Customer Concentration Risk [Member] | Accounts Receivable [Member] | One Customer [Member]
Concentration Risk, Percentage	32%		24%
Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Number of Major Customers	1	1
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | UNITED STATES
Concentration Risk, Percentage	94%	92%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | One Customer [Member]
Concentration Risk, Percentage	17%	13%

Note 2 - Summary of Significa_4

Note 2 - Summary of Significant Accounting Policies - Product Warranty (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Beginning balance	$ 193	$ 109
Warranty provision	15	19
Usage/Release	(26)	(14)
Ending balance	$ 182	$ 114

Note 2 - Summary of Significa_5

Note 2 - Summary of Significant Accounting Policies - Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Net loss applicable to common stockholders	$ (3,674)	$ (5,862)
Weighted average common stock outstanding, basic and diluted (in shares)	1,477	548
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (2.49)	$ (10.7)

Note 2 - Summary of Significa_6

Note 2 - Summary of Significant Accounting Policies - Anti-dilutive Securities (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Potentially dilutive securities (in shares)	634,683	665,799
Common Stock Warrants [Member]
Potentially dilutive securities (in shares)	467,343	525,415
Common Stock Options [ member]
Potentially dilutive securities (in shares)	15	15
Preferred Stock [Member]
Potentially dilutive securities (in shares)	50,409	60,961
Restricted Stock Units (RSUs) [Member]
Potentially dilutive securities (in shares)	116,916	79,408

Note 3 - Inventories - Schedule

Note 3 - Inventories - Schedule of Inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Raw materials	$ 2,741	$ 3,203
Work-in-process	130	25
Finished products	1,691	2,070
Total inventories	$ 4,562	$ 5,298

Note 4 - Borrowings (Details Te

Note 4 - Borrowings (Details Textual)				3 Months Ended
	Aug. 02, 2023 USD ($) $ / shares shares	Aug. 10, 2022 USD ($)	Feb. 14, 2018 USD ($)	Mar. 31, 2024 USD ($) $ / shares	Mar. 31, 2023 USD ($)	Apr. 02, 2024 USD ($)	Mar. 04, 2024	Jan. 26, 2024 USD ($)	Dec. 31, 2023 USD ($) $ / shares	Dec. 31, 2022 $ / shares	Jun. 15, 2016 USD ($)	Sep. 22, 2015 USD ($)
Preferred Stock, Par or Stated Value Per Share | $ / shares				$ 0.001					$ 0.001	$ 0.001
Series E Preferred Stock [Member]
Preferred Stock, Par or Stated Value Per Share | $ / shares	$ 1,000
Preferred Stock, Convertible, Conversion Ratio	93
Preferred Stock, Convertible, Conversion Price (in dollars per share) | $ / shares	$ 10.725
Preferred Stock, Convertible, Beneficial Ownership Percentage	19.99%
Conversion of CRG Loan Into Series E Convertible Preferred Stock [Member]
Debt Conversion, Original Debt, Amount	$ 1,920,000
Debt Conversion, Converted Instrument, Shares Issued (in shares) | shares	1,920
Loan Agreement [Member]
Debt Instrument, Financing Fee Percentage							7%
CRG [Member] | Loan Agreement [Member]
Debt Agreement, Maximum Borrowing Capacity												$ 50,000,000
Debt Instrument, Covenant Compliance, Minimum Liquidity Requirement			$ 3,500,000
Debt Instrument, Interest Rate, Stated Percentage		12.50%
Debt Instrument, Periodic Payment		$ 2,400,000
Long-Term Debt, Maturity, Year Four		9,400,000
Long-Term Debt, Maturity, Year Five		$ 9,400,000
Debt Instrument, Redemption Initial Prepayment Premium Percentage		5%
Debt Instrument, Redemption Annual Decline in Prepayment Premium Percentage		1%
Debt Instrument, Financing Fee Percentage		1.50%
Debt Instrument, Final Facility Fee Percentage		15%
Debt Instrument, Covenant Compliance Cash and Certain Cash Equivalents Minimum		$ 3,500,000
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net				$ 150,000					$ 166,000			1,300,000
Amortization of Debt Discount (Premium)				16,000	$ 21,000
Interest Expense, Debt				$ 458,000,000,000	$ 507,000,000,000
CRG [Member] | Loan Agreement [Member] | Forecast [Member]
Debt Instrument, Covenant Compliance, Minimum Liquidity Requirement						$ 3,500,000
CRG [Member] | Loan Agreement [Member] | Series A Preferred Stock Purchase Agreement with CRG [Member]
Debt Conversion, Original Debt, Amount			38,000,000
Debt Conversion, Fees and Prepayment Premium Amount			$ 3,800,000
CRG [Member] | Loan Agreement [Member] | First Tranche, Borrowed on September 22, 2015 [Member]
Debt Instrument, Face Amount												$ 30,000,000
CRG [Member] | Loan Agreement [Member] | Second Tranche, Borrowed on June 15, 2016 [Member]
Debt Instrument, Face Amount											$ 10,000,000
CRG [Member] | Loan Agreement Amendment No. 7 [Member]
Debt Instrument, Covenant Compliance, Minimum Liquidity Requirement								$ 1,000,000

Note 4 - Borrowings - Schedule

Note 4 - Borrowings - Schedule of Debt (Details) - CRG [Member] - Loan Agreement [Member] $ in Thousands	Mar. 31, 2024 USD ($)
2024 (remaining nine months of the year)	$ 0
Long-Term Debt, Maturity, Year Two	0
Long-Term Debt, Maturity, Year Three	0
Long-Term Debt, Maturity, Year Four	11,378
Long-Term Debt, Maturity, Year Five	13,017
Total	24,395
Less: Amount of PIK additions and final facility fee to be incurred subsequent to March 31, 2024	(9,494)
Less: Amount representing debt issuance costs	(150)
Borrowings, current portion, as of March 31, 2024	$ 14,751

Note 5 - Leases (Details Textua

Note 5 - Leases (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 06, 2024	Dec. 31, 2023	Dec. 31, 2019
Lessee, Operating Lease, Liability, to be Paid	$ 2,100,000		$ 1,300,000		$ 7,100,000
Operating Lease, Weighted Average Remaining Lease Term	1 year 8 months 12 days
Finance Lease, Right-of-Use Asset, Amortization	$ 2,200,000
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 2,200,000
Lessee, Operating Lease, Discount Rate	6.50%
Operating Lease, Expense, Excluding Maintenance Fee and Other Expense, Monthly	$ 105,000
Operating Lease, Expense	315,000	$ 314,000
Operating Lease, Cost	90,000	65,000
Operating Lease, Right-of-Use Asset, Periodic Reduction	292,000	$ 280,000
Prepaid Rent	$ 9,000			$ 13,000

Note 5 - Leases - Future Operat

Note 5 - Leases - Future Operating Lease Payments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 06, 2024	Dec. 31, 2023	Dec. 31, 2019
2024	$ 934
Lessee, Operating Lease, Liability, to be Paid, Year Two	1,166
Total	2,100	$ 1,300		$ 7,100
Less: Imputed interest	(109)
Leasehold liability as of June 30, 2023	$ 1,991		$ 1,102

Note 5 - Leases - ROU Assets an

Note 5 - Leases - ROU Assets and Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Operating lease	$ 1,991	$ 1,102
Total right of use assets	1,991	1,102
Leasehold liability, current portion	1,156	1,102
Leasehold liability, long-term portion	835	0
Total lease liabilities	$ 1,991	$ 1,102

Note 6 - Commitments and Cont_2

Note 6 - Commitments and Contingencies (Details Textual) $ in Millions	Mar. 31, 2024 USD ($)
Purchase Commitment [Member]
Purchase Obligation	$ 0.4

Note 7 - Stockholders' Equity_2

Note 7 - Stockholders' Equity (Details Textual) $ / shares in Units, $ in Millions				3 Months Ended
	Mar. 05, 2024 shares	Mar. 04, 2024 $ / shares shares	Aug. 02, 2023 $ / shares shares	Mar. 31, 2024 USD ($) $ / shares shares	Mar. 31, 2023 shares	Dec. 31, 2023 $ / shares shares	Dec. 23, 2023 shares	Sep. 30, 2023 $ / shares shares	Dec. 31, 2022 $ / shares shares	Jan. 14, 2022 $ / shares shares	Feb. 16, 2018 $ / shares
Preferred Stock, Shares Authorized (in shares)				5,000,000		5,000,000		5,000,000	5,000,000
Preferred Stock, Par or Stated Value Per Share | $ / shares				$ 0.001		$ 0.001			$ 0.001
Preferred Stock, Shares Outstanding (in shares)				19,229		62,881
Preferred Stock, Shares Issued				19,229		62,881
Securities Purchase Agreement, Number of Shares to Convert	10,000
Common Stock, Shares Authorized				100,000,000		100,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares		$ 0.001		$ 0.001				$ 0.001	$ 0.001
Common Stock, Shares, Outstanding, Ending Balance (in shares)				1,586,434		1,279,928
Common Stock, Shares, Issued (in shares)				1,586,434		1,279,928
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		40,938		497,034		456,096	456,096
Common Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights										40,938
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares										$ 3.664
Warrants and Rights Outstanding, Term										5 years
March 2024 Offering [Member]
Stock Issued During Period, Shares, New Issues	75,327
Common Stock [Member]
Shares Issued, Price Per Share | $ / shares		$ 3.664		$ 3.664
Stock Issued During Period, Shares, New Issues		75,327			794
Series A Preferred Stock [Member]
Preferred Stock, Shares Outstanding (in shares)				60,876					60,876
Series A-1 Preferred Stock [Member]
Preferred Stock, Shares Authorized (in shares)				10,000
Preferred Stock, Excess Fair Value | $				$ 1.9
Preferred Stock, Stated Value | $ / shares				$ 1,000
Preferred Stock, Convertible, Conversion Ratio				273
Preferred Stock, Convertible, Shares Issuable	2,729,257			2,729,257
Securities Purchase Agreement, Number of Shares to Convert				10,000
Series B Preferred Stock [Member]
Preferred Stock, Par or Stated Value Per Share | $ / shares											$ 0.001
Preferred Stock, Shares Outstanding (in shares)								85	85
Preferred Stock, Convertible, Conversion Price (in dollars per share) | $ / shares								$ 3.664	$ 3.664
Series E Preferred Stock [Member]
Preferred Stock, Par or Stated Value Per Share | $ / shares			$ 1,000
Preferred Stock, Shares Outstanding (in shares)								1,920
Preferred Stock, Convertible, Conversion Ratio			93
Preferred Stock, Convertible, Shares Issuable			178,560
Preferred Stock, Convertible, Conversion Price (in dollars per share) | $ / shares			$ 10.725
Preferred Stock, Convertible, Beneficial Ownership Percentage			19.99%
Preferred Stock, Dividend Rate, Percentage			8%
Dividends, Preferred Stock | $				$ 0.1
Series F Preferred Stock [Member]
Preferred Stock, Par or Stated Value Per Share | $ / shares		$ 0.001
Preferred Stock, Shares Outstanding (in shares)				7,224
Preferred Stock, Stated Value | $ / shares		$ 1,000
Preferred Stock, Convertible, Conversion Ratio		273
Shares Issued, Price Per Share | $ / shares		$ 1,000
Preferred Stock, Convertible, Beneficial Ownership Percentage		19.90%
Preferred Stock, Dividend Rate, Percentage		5%
Dividends, Preferred Stock | $				$ 0.1
Stock Issued During Period, Shares, New Issues		7,224
Preferred Stock Dividend Rate, Percentage, Thereafter Third Anniversary Of Issuance		8%
Series F Convertible Preferred Stock [Member]
Preferred Stock, Convertible, Shares Issuable		1,971,616
Series D Preferred Stock [Member] | January 2022 offering [Member] | Common Warrants [Member]
Conversion of Warrants Allowed Maximum Ownership of Common Stock Percentage										4.99%
Conversion of Warrants Allowed Maximum Ownership of Common Stock Percentage upon Election										9.99%

Note - 7 Stockholder's Equity -

Note - 7 Stockholder's Equity - Outstanding Warrants (Details) - $ / shares	Mar. 31, 2024	Mar. 04, 2024	Dec. 31, 2023	Dec. 23, 2023
Total Outstanding and Exercisable (in shares)	41,088,437			41,047,499
Underlying Shares of Common Stock (in shares)	497,034	40,938	456,096	456,096
Series 1 February 2018 Warrants [Member]
Total Outstanding and Exercisable (in shares)	8,979,000			8,979,000
Underlying Shares of Common Stock (in shares)	2,993			2,993
Exercise Price per Share (in dollars per share)	$ 6,000			$ 6,000
Series 2 February 2018 Warrants [Member]
Total Outstanding and Exercisable (in shares)	8,709,500			8,709,500
Underlying Shares of Common Stock (in shares)	2,903			2,903
Exercise Price per Share (in dollars per share)	$ 6,000			$ 6,000
Placement agent warrants issued in the January 2022 financing [Member]
Total Outstanding and Exercisable (in shares)	1,330,000			1,330,000
Underlying Shares of Common Stock (in shares)	4,433			4,433
Exercise Price per Share (in dollars per share)	$ 150			$ 150
Warrants Issued in the January 2022 Financing [Member]
Total Outstanding and Exercisable (in shares)	16,150,000			16,150,000
Underlying Shares of Common Stock (in shares)	53,833			53,833
Exercise Price per Share (in dollars per share)	$ 144			$ 144
Series A Private Investment Options Issued in August 2022 Financing [Member]
Total Outstanding and Exercisable (in shares)	2,853,883			2,853,883
Underlying Shares of Common Stock (in shares)	190,259			190,259
Exercise Price per Share (in dollars per share)	$ 22.53			$ 22.53
Series B Private Investment Options Issued in August 2022 Financing [Member]
Total Outstanding and Exercisable (in shares)	2,853,883			2,853,883
Underlying Shares of Common Stock (in shares)	190,259			190,259
Exercise Price per Share (in dollars per share)	$ 22.53			$ 22.53
Placement Agent Private Investment Options Issued in August 2022 Financing [Member]
Total Outstanding and Exercisable (in shares)	171,233			171,233
Underlying Shares of Common Stock (in shares)	11,416			11,416
Exercise Price per Share (in dollars per share)	$ 32.85			$ 32.85
Advisor Warrants Issued In The March 2024 Financing [Member]
Total Outstanding and Exercisable (in shares)	40,938
Underlying Shares of Common Stock (in shares)	40,938
Exercise Price per Share (in dollars per share)	$ 3.664

Note 8 - Stock-based Compensa_3

Note 8 - Stock-based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
	Dec. 22, 2023	Mar. 31, 2024	Mar. 31, 2023	Mar. 28, 2024
Share Price				$ 3.1
Share-Based Payment Arrangement, Expense		$ 1,096	$ 245
Restricted Stock Units (RSUs) [Member]
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount		$ 800
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition		9 months 18 days
Sharebased Compensation Arrangement by Sharebased Payment Award Equity Instruments Other than Options Nonvested Fair Value		$ 400
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value		1,000	100
Share-Based Payment Arrangement, Expense		$ 1,100	$ 200
The 2015 Employee Stock Purchase Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized	300,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant		68,109

Note 8 - Stock-Based Compensa_4

Note 8 - Stock-Based Compensation - Stock Option Activity (Details) - Restricted Stock Units (RSUs) [Member] - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Awards outstanding, shares (in shares)	90,190
Awards outstanding, Weighted Average Grant Date Fair Value (in dollars per share)	$ 18.45
Awards outstanding, Weighted Average Remaining Contractual Term (Year)	9 months 18 days	1 year 14 days
Awarded, shares (in shares)	394,105
Awarded, Weighted Average Grant Date Fair Value (in dollars per share)	$ 2.75
Released, shares (in shares)	(368,503)
Released, Weighted Average Grant Date Fair Value (in dollars per share)	$ 4.89
Forfeited, shares (in shares)	0
Forfeited, , Weighted Average Grant Date Fair Value (in dollars per share)	$ 0
Awards outstanding, shares (in shares)	115,792	90,190
Awards outstanding, Weighted Average Grant Date Fair Value (in dollars per share)	$ 8.16	$ 18.45

Note 8 - Stock-based Compensa_5

Note 8 - Stock-based Compensation - Noncash Stock-based Compensation Expense Related to Stock Options, ESPP, and RSUs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Allocated Share-based Compensation Expense	$ 1,096	$ 245
Cost of Sales [Member]
Allocated Share-based Compensation Expense	158	28
Research and Development Expense [Member]
Allocated Share-based Compensation Expense	314	83
Selling, General and Administrative Expenses [Member]
Allocated Share-based Compensation Expense	$ 624	$ 134