Avinger (AVGR) 10-K 22 Mar 22 2021 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2021	Mar. 18, 2022	Jun. 30, 2021
Document Information [Line Items]
Entity Central Index Key	0001506928
Entity Registrant Name	Avinger Inc
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2021
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Document Transition Report	false
Entity File Number	001-36817
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 Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
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 Public Float			$ 116,800,000
Entity Common Stock, Shares Outstanding		5,428,770
Auditor Name	Moss Adams LLP
Auditor Location	San Francisco, CA
Auditor Firm ID	659

Balance Sheets

Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 19,497	$ 22,185
Accounts receivable, net of allowance for doubtful accounts of $6 and $19 at December 31, 2021 and 2020, respectively	1,393	1,484
Inventories	4,601	3,876
Prepaid expenses and other current assets	300	350
Total current assets	25,791	27,895
Right of use asset	3,179	4,063
Property and equipment, net	95	727
Other assets	420	510
Total assets	29,485	33,195
Current liabilities:
Accounts payable	1,394	694
Accrued compensation	1,609	1,703
Accrued expenses and other current liabilities	718	669
Leasehold liability, current portion	985	806
Borrowings, current portion	0	3,590
Total current liabilities	4,706	7,462
Borrowings, long-term portion	12,287	9,400
Leasehold liability, long-term portion	2,194	3,257
Other long-term liabilities	575	0
Total liabilities	19,762	20,119
Stockholders’ equity:
Convertible preferred stock issuable in series, par value of $0.001; Shares authorized: 5,000,000 at December 31, 2021 and 2020; Shares issued and outstanding: 56,451 and 52,369 at December 31, 2021 and 2020, respectively; aggregate liquidation preference related to Series A convertible preferred stock of $56,366 and $52,191 at December 31, 2021 and 2020, respectively	0	0
Common stock, par value of $0.001; Shares authorized: 100,000,000 at December 31, 2021 and 2020; Shares issued and outstanding: 4,778,263 and 4,246,308 at December 31, 2021 and 2020, respectively	96	85
Additional paid-in capital	394,380	380,332
Accumulated deficit	(384,753)	(367,341)
Total stockholders’ equity	9,723	13,076
Total liabilities and stockholders’ equity	$ 29,485	$ 33,195

Balance Sheets (Parentheticals)

Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Preferred stock, par value (in dollars per share)	$ 0.001
Preferred stock, shares authorized (in shares)	5,000,000
Preferred stock, shares issued (in shares)	56,451	52,369
Common stock, par value (in dollars per share)	$ 0.001
Common stock, shares authorized (in shares)	100,000,000
Common stock, shares issued (in shares)	4,778,263

Statements of Operations and Co

Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Revenues	$ 10,130	$ 8,761
Cost of revenues	6,706	6,143
Gross profit	3,424	2,618
Operating expenses:
Research and development	5,900	5,695
Selling, general and administrative	15,625	14,327
Total operating expenses	21,525	20,022
Loss from operations	(18,101)	(17,404)
Interest income	3	34
Interest expense	(1,651)	(1,692)
Other income, net	2,337	56
Net loss and comprehensive loss	(17,412)	(19,006)
Accretion of preferred stock dividends	(4,175)	(3,866)
Net loss applicable to common stockholders	$ (21,587)	$ (22,872)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (4.57)	$ (9.29)
Weighted average common shares used to compute net loss per share, basic and diluted (in shares)	4,722	2,462

Statements of Stockholders' Equ

Statements of Stockholders' Equity - USD ($) $ in Thousands	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2019	48,503	518,233
Balance at Dec. 31, 2019	$ 0	$ 10	$ 355,220	$ (348,335)	$ 6,895
Issuance of common stock in public offerings, net of commissions and issuance costs (in shares)	0	3,707,016
Issuance of common stock in public offerings, net of commissions and issuance costs	$ 0	$ 74	23,572	0	23,646
Employee stock-based compensation	$ 0	$ 0	1,513	0	1,513
Issuance of common stock under officers and directors purchase plan and vesting of restricted stock units (in shares)	0	21,059
Issuance of common stock under officers and directors purchase plan and vesting of restricted stock units	$ 0	$ 1	27	0	28
Issuance of Series A preferred stock to pay dividends (in shares)	3,866	0
Issuance of Series A preferred stock to pay dividends	$ 0	$ 0	3,866	0	3,866
Accretion of Series A preferred stock dividends	0	0	(3,866)	0	(3,866)
Net and comprehensive loss	0	0	0	(19,006)	(19,006)
Net loss	$ 0	$ 0	0	(19,006)	(19,006)
Balance (in shares) at Dec. 31, 2020	52,369	4,246,308
Balance at Dec. 31, 2020	$ 0	$ 85	380,332	(367,341)	13,076
Issuance of common stock in public offerings, net of commissions and issuance costs (in shares)	0	500,000
Issuance of common stock in public offerings, net of commissions and issuance costs	$ 0	$ 10	13,033	0	13,043
Employee stock-based compensation	$ 0	$ 0	1,015	0	1,015
Issuance of Series A preferred stock to pay dividends (in shares)	4,175	0
Issuance of Series A preferred stock to pay dividends	$ 0	$ 0	4,175	0	4,175
Accretion of Series A preferred stock dividends	0	0	(4,175)	0	(4,175)
Net and comprehensive loss	$ 0	$ 0	0	(17,412)	(17,412)
Conversion of Series B preferred stock into common stock (in shares)	(93)	18,600
Issuance of common stock upon vesting of restricted stock units (in shares)	0	13,355
Issuance of common stock upon vesting of restricted stock units	$ 0	$ 1	0	0	1
Net loss	$ 0	$ 0	0	(17,412)	(17,412)
Balance (in shares) at Dec. 31, 2021	56,451	4,778,263
Balance at Dec. 31, 2021	$ 0	$ 96	$ 394,380	$ (384,753)	$ 9,723

Statements of Cash Flows

Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Net loss	$ (17,412)	$ (19,006)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	687	897
Amortization of debt issuance costs and debt discount	86	168
Stock-based compensation	1,015	1,513
Noncash interest expense and other charges	1,564	1,524
Change in right of use asset	133	169
Provision for excess and obsolete inventories	125	528
Gain on extinguishment of debt	(2,353)	0
Other non-cash charges	2	(54)
Changes in operating assets and liabilities:
Accounts receivable	89	(1)
Inventories	(849)	(490)
Prepaid expenses and other current assets	50	(48)
Other assets	(43)	5
Accounts payable	679	31
Accrued compensation	(94)	(79)
Accrued expenses and other current liabilities	49	15
Other long-term liabilities	575	(7)
Net cash used in operating activities	(15,697)	(14,835)
Cash flows from investing activities
Purchase of property and equipment	(34)	0
Proceeds from sale of property and equipment	0	65
Net cash provided by (used in) investing activities	(34)	65
Cash flows from financing activities
Proceeds from the issuance of common stock in public offerings, net of commissions and issuance costs	13,043	23,646
Proceeds from borrowings, net of issuance costs	0	2,330
Proceeds from issuance of common stock under officers’ and directors’ purchase plan	0	36
Net cash provided by financing activities	13,043	26,012
Net change in cash and cash equivalents	(2,688)	11,242
Cash and cash equivalents, beginning of period	22,185	10,943
Cash and cash equivalents, end of period	19,497	22,185
Noncash investing and financing activities:
Accretion of Series A preferred stock dividends	4,175	3,866
Issuance of Series A preferred stock as dividend payment	4,175	3,866
Reclassification of right of use asset to prepaid rent	(133)	(169)
Purchases of property and equipment in accounts payable	$ 21	$ 0

Note 1 - Organization

Note 1 - Organization	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Nature of Operations [Text Block]	1. Organization, Nature of Business Avinger, Inc. (the “Company”), a Delaware corporation, was incorporated in March 2007. “OCT”) Liquidity Matters In the course of its activities, the Company has incurred losses and negative cash flows from operations since its inception. As of December 31, 2021, December 31, 2021, January 2022 second 2023. January 2020 April 2020 April 2021, April May 2020, June July 2020, August September 2020, February 2021. not may The Company can provide no not may twelve no 19 second 2020, 19 July 2020. On September 22, 2021, not 5550 2 $1 30 180 March 21, 2022, $1 ten no March 14, 2022, 1 20 no $1 ten The Company has not 5810 3 180 March 17, 2022, not not If the Company is unable to raise additional capital in sufficient amounts or on terms acceptable to it, the Company may one not Public Offerings On January 31, 2020, February 2018 On April 30, 2020, May 6, 2020, February 2018 On June 26, 2020, July 9, 2020, On August 6, 2020, March 7, 2019 ( August 11, 2020, On August 25, 2020, September 1, 2020, On February 2, 2021, January 2022 On January 14, 2022, “January 2022 In connection with the January 2022 March 11, 2022 1 1 March 11, 2022, 1 5:00 March 14, 2022. Pursuant to the purchase agreement, the Company filed a certificate of designation (the “Certificate of Designation”) with the Secretary of State of Delaware designating the rights, preferences and limitations of the shares of Series D preferred stock, which became effective on January 14, 2022. no March 11, 2022, no The holders of the Series D preferred stock are entitled to dividends, on an as-if converted basis, equal to dividends actually paid, if any, on shares of Common Stock. The Series D preferred stock is convertible into shares of common stock at a conversion price of $8.00 per share, as adjusted for the most recent reverse stock split. The conversion price can be adjusted pursuant to the Certificate of Designation for stock dividends and stock splits, subsequent rights offerings, pro rata distributions of dividends or the occurrence of a fundamental transaction (as defined in the Certificate of Designation). The Series D preferred stock can be converted at the option of the holders at any time. In addition, subject to the satisfaction of certain conditions, the Company may 4.99% 9.99% may, not 9.99%. The Common Warrants have an exercise price of $9.60 per share and become exercisable beginning July 14, 2022. five July 14, 2027. five January 2022 January 12, 2027.

Note 2 - Summary of Significant

Note 2 - Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Basis of Presentation and Significant Accounting Policies [Text Block]	2. Basis of Presentation The accompanying 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 Securities and Exchange Commission (“SEC”). On March 11, 2022, 1 March 14, 2022. not 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 may may Fair Value of Financial Instruments The Company has evaluated the estimated fair value of its financial instruments as of December 31, 2021 2020. Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three December 31, 2021 2020, December 31, 2021 2020. 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 December 31, 2021 2020. The Company’s accounts receivable are due from a variety of healthcare organizations in the United States and select international markets. At December 31, 2021 2020, December 31, 2021, one December 31, 2020, The Company manufactures its commercial products in-house, including the Pantheris and Ocelot family of catheters. Certain of the Company’s product components and sub-assemblies are manufactured by sole suppliers, including internally. Disruption in component or sub-assembly supply from these manufacturers or from in-house production would have a negative impact on the Company’s financial position and results of operations. The Company is subject to certain risks, including that its devices may not no not third Existing or future devices developed by the Company may may may Disruption of our supply chain capabilities due to trade restrictions, political instability, severe weather, natural disasters, public health crises such as the ongoing COVID - 19 - 19 Accounts Receivable Trade accounts receivable are recorded at the invoiced amount and do not not Accounts receivable allowance for doubtful accounts provision and recoveries or write-offs are summarized as follows (in thousands): 2021 2020 Beginning balance $ 19 $ 19 Provision 2 26 Recoveries/write-offs (15 ) (26 ) Ending balance $ 6 $ 19 Inventories Inventories are valued at the lower of cost or net realizable value. Cost is determined using the first first not not Property and Equipment Property and equipment are recorded at cost. Repairs and maintenance costs are expensed as incurred. Depreciation and amortization are calculated using the straight-line method over the estimated useful lives of the assets of generally three five Impairment of Long-Lived Assets The Company reviews long-lived assets, including property and equipment, for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not not December 31, 2021. Revenue Recognition The Company’s revenues are derived from ( 1 2 3 1. Lightbox console sales: Provided all other criteria for revenue recognition have been met, the Company recognizes revenue for Lightbox console sales directly to end customers when delivery and acceptance occurs, which is defined as receipt by the Company of an executed form that the installation process is complete. 2. Sales of disposables: Disposable revenues consist of sales of the Company’s catheters and accessories and are recognized when the product has shipped, risk of loss and title has passed to the customer and collectability is reasonably assured. 3. Service revenue: Service contract revenue consists of preventative maintenance, upgrades, and service contracts. Service contracts are recognized ratably over the term of the service period and maintenance contract revenue is recognized as work is performed. To date, service revenue has been insignificant. The Company offers its customers the ability to purchase or lease the Lightbox console. In addition, the Company provides a Lightbox under a limited commercial evaluation program to allow accounts to install and utilize the Lightbox for a limited trial period. When a Lightbox is placed under a lease agreement or under a commercial evaluation program, the Company retains title to the equipment and it remains capitalized on its balance sheet under property and equipment. Depreciation expense on these placed Lightboxes is recorded to cost of revenues on a straight-line basis. The costs to maintain these placed Lightboxes are charged to cost of revenues as incurred. The Company evaluates its lease and commercial evaluation program agreements and accounts for these contracts under the guidance in Accounting Standards Codification (“ASC”) 842, Leases No. 2014 09, Revenue from Contracts with Customers (Topic 606 The Company assessed whether the embedded lease is an operating lease or sales-type lease. Based on the Company’s assessment of the guidance and given that any payments under the lease agreements are dependent upon contingent future sales, it was determined that collectability of the minimum lease payments is not not For sales through distributors, the Company recognizes revenue when control of the product transfers from the Company to the distributor. The distributors are responsible for all marketing, sales, training and warranty in their respective territories. The standard terms and conditions contained in the Company’s distribution agreements do not not Cost of Revenues Cost of revenues consists primarily of manufacturing overhead costs, material costs and direct labor. A significant portion of the Company’s cost of revenues currently consists of manufacturing overhead costs. These overhead costs include the cost of quality assurance, material procurement, inventory control, facilities, equipment and operations supervision and management. Cost of revenues also includes depreciation expense for the Lightboxes under lease and evaluation agreements, product warranty costs, product written-off due to excess or obsolescence, and certain direct costs such as shipping costs. Product Warranty Costs The Company typically offers a one 2021 2020 Beginning balance $ 193 $ 215 Warranty provision 49 142 Usage/Release (55 ) (164 ) Ending balance $ 187 $ 193 Research and Development The Company expenses research and development costs as incurred. Research and development expenses include personnel and personnel-related costs, costs associated with pre-clinical and clinical development activities, and costs for prototype products that are manufactured prior to market approval for that prototype product, and internal and external costs associated with the Company’s regulatory compliance, including the costs of outside consultants and contractors that assist in the process of submitting and maintaining regulatory filings, and overhead costs, including allocated facility and related expenses. Clinical Trials The Company accrues and expenses costs for its clinical trial activities performed by third Stock-Based Compensation Stock-based compensation for the Company includes amortization related to all stock options, restricted stock units (“RSU”), based on the grant-date estimated fair value. The fair value of stock options is estimated on the date of grant using the Black-Scholes option pricing model and recognized as expense on a straight-line basis over the vesting period of the award. The Company has not 2017. No. 2016‑09, Compensation-Stock Compensation (Topic 718 Foreign Currency The Company records net gains and losses resulting from foreign exchange transactions as a component of foreign currency exchange losses in other income, net. During the years ended December 31, 2021 2020, Income Taxes The Company utilizes the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on differences between financial reporting and tax reporting bases of assets and liabilities and are measured using enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. The Company’s policy is to record interest and penalties on uncertain tax positions as income tax expense when they occur. During the years ended December 31, 2021 2020, not Net Loss per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable 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 attributable to common stockholder 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 December 31, 2021 2020, Net loss per share attributable to common stockholders was determined as follows (in thousands, except per share data): Year Ended December 31, 2021 2020 Net loss applicable to common stockholders $ (21,587 ) $ (22,872 ) Weighted average common stock outstanding, basic and diluted 4,722 2,462 Net loss per share attributable to common stockholders, basic and diluted $ (4.57 ) $ (9.29 ) 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: Year Ended December 31, 2021 2020 Common stock warrants equivalents 135,430 137,700 Common stock options 335 351 Convertible preferred stock 52,289 48,503 Unvested restricted stock units 17,793 35,971 205,847 222,525 Comprehensive Loss For the years ended December 31, 2021 2020, no Segment and Geographical Information The Company operates and manages its business as one December 31, 2021 2020, Recent Accounting Pronouncements Recently adopted accounting standards In December 2019, 2019 12, Income Taxes (Topic 740 January 1, 2021. not Recent accounting standards not In August 2020, 2020 06, Debt Debt with Conversion and Other Options (Subtopic 470 20 Contracts in Entity s Own Equity (Subtopic 815 40 s Own Equity not 815 first 2024 not In May 2021, No. 2021 04, Issuer s Accounting for Certain Modifications of Exchanges of Freestanding Equity-Classified Written Call Options January 1, 2022 not

Note 3 - Fair Value Measurement

Note 3 - Fair Value Measurements	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Fair Value Disclosures [Text Block]	3. The Company measures certain financial assets and liabilities at fair value on a recurring basis. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. A three Level 1—Quoted Level 2—Inputs 1 not Level 3—Unobservable no As of December 31, 2021 2020, 1 December 31, 2021 2020, 2 3. no December 31, 2021 2020. In January 2022, 3.

Note 4 - Inventories

Note 4 - Inventories	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Inventory Disclosure [Text Block]	4. Inventories consisted of the following (in thousands): December 31, 2021 2020 Raw materials $ 2,503 $ 1,904 Work-in-process 1 180 Finished products 2,097 1,792 Total inventories $ 4,601 $ 3,876

Note 5 - Property and Equipment

Note 5 - Property and Equipment, Net	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Property, Plant and Equipment Disclosure [Text Block]	5. Property and equipment, net, consisted of the following (in thousands): December 31, 2021 2020 Equipment held by customers $ 2,362 $ 2,746 Machinery and equipment 1,391 1,679 Computer software 122 122 Computer equipment 173 144 Furniture and fixture 78 78 Leasehold improvements 320 311 Total property and equipment, gross 4,446 5,080 Less: Accumulated depreciation and amortization (4,351 ) (4,353 ) Total property and equipment, net $ 95 $ 727 Depreciation expense for the years ended December 31, 2021 2020, Property and equipment include certain equipment that is leased to customers and located at customer premises. The Company retains the ownership of the equipment held for evaluation and has the right to remove the equipment if it is not December 31, 2021 2020, December 31, 2021. December 31, 2020.

Note 6 - Accrued Expenses and O

Note 6 - Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Accounts Payable, Accrued Liabilities, and Other Liabilities Disclosure, Current [Text Block]	6. Accrued expenses and other current liabilities consisted of the following (in thousands): December 31, 2021 2020 Accrued product warranty costs $ 187 $ 193 Accrued clinical trial costs 153 96 Deferred revenue 123 28 Accrued travel expenses 118 104 Accrued sales and use tax 33 43 Accrued professional fees — 65 Other accrued liabilities 104 140 Total accrued expenses and other current liabilities $ 718 $ 669

Note 7 - Borrowings

Note 7 - Borrowings	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Debt Disclosure [Text Block]	7. CRG On September 22, 2015, March 29, 2017. September 22, 2015. June 15, 2016 On February 14, 2018, On March 2, 2020, No. 3 ● extend the period that the Company can make interest payments in payment in kind (“PIK”) to June 30, 2021; ● lower the Minimum Revenue Covenants to $10 million for 2020, 2021, 2022; ● insert certain terms to clarify that all fees, including the prepayment premium, are due if the obligations are accelerated; and ● insert a new provision to make clear that to the extent the Company divides its assets/liabilities into divisions, such assets/liabilities will be treated as transferred to a third On May 12, 2020, No. 4 ● grant to the Company the right to optionally prepay in whole or in part the outstanding principal amount of the Loans for the Redemption Price, subject to certain conditions; and ● waive the Company’s requirement to comply with the Minimum Revenue Covenant for 2020. On January 22, 2021, No. 5 ● extend the maturity date of the Loan Agreement from June 30, 2023 December 31, 2025; ● extend the interest only payment period and the period that the Company can make interest payments in PIK to December 31, 2023; ● lower the Minimum Revenue Covenants to $8 million and $10 million for 2021 2022, 2023; 2024, 2025; ● change the date under the on-going stand-alone representation regarding no December 31, 2020; ● and amend the on-going stand-alone representation and stand-alone event of default 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 not Under the amended Loan Agreement, no first 2024. not first 2024, 2024 2025. December 31, 2025. The Company may no seven 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 revenue requirements 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, and the Company has to achieve certain minimum revenues. If the Company fails to meet the applicable minimum revenue target in any calendar year, the Loan Agreement provides the Company with a cure right if it prepays a portion of the outstanding principal equal to 2.0 times the revenue shortfall. 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 As of December 31, 2021, As of December 31, 2021, Year Ending December 31, 2022 $ — 2023 — 2024 9,045 2025 10,339 Total 19,384 Less: Amount of PIK additions and final facility fee to be incurred subsequent to December 31, 2021 (6,765 ) Less: Amount representing debt issuance costs (332 ) Borrowings, long term portion, as of December 31, 2021 $ 12,287 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 December 31, 2021 2020, December 31, 2021 2020, December 31, 2021 2020, As of December 31, 2021, Paycheck Protection Program On April 23, 2020, The Loan, which was in the form of a promissory note, dated April 20, 2020 ( April 20, 2022 1% six may no The PPP was administered by the U.S. Small Business Administration (the “SBA”). The SBA was given the authority under the PPP to forgive loans if all employees were kept on the payroll for a required period and the loan proceeds were used for payroll, rent and utilities. The Company applied for debt forgiveness in December 2020. On April 17, 2021, no April 2021 For the years ended December 31, 2021 2020,

Note 8 - Leases

Note 8 - Leases	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Lessee, Operating Leases [Text Block]	8. 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 lease includes a rent holiday concession and escalation clauses for increased rent over the lease term. Rent expense is recognized using the straight-line method over the term of the lease. The Company records deferred rent calculated as the difference between rent expense and the cash rental payments. The lease will expire on November 30, 2024. November 2024, December 1, 2019. December 31, 2021 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 does 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 December 31, 2021 2020 December 31, 2021 2020 December 31, 2021 2020 December 31, 2021 2020, 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 December 31, 2021 ( Year Ending December 31, 2022 $ 1,162 2023 1,203 2024 1,138 Total 3,503 Less: Imputed interest (324 ) Leasehold liability as of December 31, 2021 $ 3,179 The following table shows ROU assets and lease liabilities, and the associated financial statement line items, as of December 31, 2021 December 31, 2020 ( Lease-Related Assets and Liabilities Financial Statement Line Items December 31, 2021 December 31, 2020 Right of use assets: Operating lease Right of use asset $ 3,179 $ 4,063 Total right of use assets $ 3,179 $ 4,063 Lease liabilities: Operating lease Leasehold liability, current portion $ 985 $ 806 Leasehold liability, long-term portion 2,194 3,257 Total lease liabilities $ 3,179 $ 4,063

Note 9 - Commitments and Contin

Note 9 - Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	9. 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 $1.4 million as of December 31, 2021. Indemnification In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and may may not not The Company indemnifies each of its directors and officers for certain events or occurrences, subject to certain limits, while the director is or was serving at the Company’s request in such capacity, as permitted under Delaware law and in accordance with its certificate of incorporation and bylaws. The term of the indemnification period lasts as long as a director may may not Legal Proceedings The Company is not may

Note 10 - Stockholders' Equity

Note 10 - Stockholders' Equity	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Stockholders' Equity Note Disclosure [Text Block]	10. Equity Convertible Preferred Stock As of December 31, 2021, December 31, 2020, Series A Convertible Preferred Stock The holders of Series A preferred stock are entitled to receive annual accruing dividends at a rate of 8%, payable in additional shares of Series A preferred stock or cash, at the Company’s option. The shares of Series A preferred stock have a liquidation preference of $1,000 per share, no December 31, 2021 2020, December 31, 2021, December 31, 2021 2020, 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 no not December 31, 2021, December 31, 2021, Series D Convertible Preferred Stock On January 14, 2022, “January 2022 $1,000 The Series D preferred stock has no one 1 1 March 11, 2022, no The holders of the Series D preferred stock are entitled to dividends, on an as-if converted basis, equal to dividends actually paid, if any, on shares of Common Stock. The Series D preferred stock is convertible into shares of common stock at a conversion price of $8.00 per share, as adjusted for the most recent reverse stock split. The conversion price can be adjusted pursuant to the Certificate of Designation for stock dividends and stock splits, subsequent rights offerings, pro rata distributions of dividends or the occurrence of a fundamental transaction (as defined in the Certificate of Designation). The Series D preferred stock can be converted at the option of the holders at any time. In addition, subject to the satisfaction of certain conditions, we may may, not 9.99%. Common Stock At December 31, 2021, Common Stock Warrants As of December 31, 2021, January 2022 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 44,895 $ 400.00 February 2025 Series 2 Warrants issued in the February 2018 Series B financing 8,709,500 43,548 $ 400.00 February 2025 Warrants issued in the November 2018 financing 8,768,395 43,842 $ 80.00 November 2023 Placement agent warrants issued in the January 2022 financing 1,330,000 66,500 $ 10.00 January 2027 Warrants issued in the January 2022 financing 16,150,000 807,500 $ 9.60 September 2027 Total 43,936,895 1,006,285 As of December 31, 2020, 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 44,895 $ 400.00 February 2025 Series 2 Warrants issued in the February 2018 Series B financing 8,709,500 43,548 $ 400.00 February 2025 Warrants issued in the July 2018 financing 1,083,091 5,416 $ 316.00 July 2021 Warrants issued in the November 2018 financing 8,768,395 43,842 $ 80.00 November 2023 Total 27,539,986 137,701 Pursuant to the purchase agreement entered into on January 14, 2022, July 14, 2022. five July 14, 2027. The Common Warrants can be exercised at the option of the holders at any time after they become exercisable provided that shares of the Common Warrants cannot be exercised into common stock if the applicable holder would beneficially own in excess of 4.99% (or, upon election by such holder prior to the issuance of any shares of Common Warrants, 9.99%) of the Company’s outstanding common stock immediately after giving effect to the exercise. A holder of the Common Warrants may, not 9.99%. The Company also issued to the placement agent of the January 2022 five January 2022 January 12, 2027. During the year ended December 31, 2021, July 2018 December 31, 2021 2020, Stock Plans In January 2015, 2015 “2015 2015 2015 2015 first 211 December 31, 2021, 2015 Pursuant to the 2015 may not 10% not four ten Stock option activity under the Plans is set forth below: Number of Shares (in thousands) Weighted Average Exercise Price Weighted Average Remaining Contractual Life (in years) Intrinsic Value (in thousands) Balance at December 31, 2019 370 $ 26,189.40 $ — Options expired (28 ) $ 42,583.40 Options forfeited (1 ) $ 16,400.00 Balance at December 31, 2020 341 $ 24,831.70 5.81 $ — Options expired (10 ) $ 58,632.36 Options forfeited — $ — Balance at December 31, 2021 331 $ 23,815.95 4.93 $ — Exercisable at December 31, 2021 331 $ 23,815.95 4.93 $ — Vested and expected to vest at December 31, 2021 331 $ 23,815.95 4.93 $ — Additional information related to the Company’s stock options as of December 31, 2021 Options Outstanding Options Vested Weighted Weighted Weighted Average Average Average Exercise Options Remaining Exercise Number Exercise Price Outstanding Contractual Life Price Exercisable Price $ 334.00 155 6.44 $ 334.00 155 $ 334.00 $ 400.00 - 29,400.00 39 5.18 $ 17,372.31 39 $ 17,372.31 $ 36,000.00 110 3.00 $ 36,000.00 110 $ 36,000.00 $ 87,280.00 - 162,000.00 27 3.69 $ 115,913.85 27 $ 115,913.85 331 4.93 $ 23,342.58 331 $ 23,342.58 There were no options granted or exercised during either of the years ended December 31, 2021 2020. December 31, 2021 2020, December 31, 2021, no not December 31, 2021 2020. The Company’s RSUs generally vest annually over three Number of Shares Weighted Average Grant Date Fair Value Weighted Average Remaining Contractual Term Awards outstanding at December 31, 2019 45,425 $ 81.80 1.81 Awarded 2,375 $ 11.60 Released (18,407 ) $ 91.40 Forfeited (8,761 ) $ 54.40 Awards outstanding at December 31, 2020 20,632 $ 76.82 0.98 Awarded 4,500 $ 32.20 Released (13,355 ) $ 104.23 Forfeited (1,727 ) $ 53.79 Awards outstanding at December 31, 2021 10,050 $ 24.37 0.72 As of December 31, 2021, one December 31, 2021 December 31, 2021 December 31, 2021 2020, December 31, 2021 2020, 2018 On August 22, 2018, may August 28, 2019 March 10, 2020, no December 31, 2021. December 31, 2020 December 31, 2021,

Note 11 - Stock-based Compensat

Note 11 - Stock-based Compensation	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Share-based Payment Arrangement [Text Block]	11. Total noncash stock-based compensation expense relating to the Company’s stock options and RSUs recognized, before taxes, during the years ended December 31, 2021 2020, Year Ended December 31, 2021 2020 Cost of revenues $ 101 $ 132 Research and development expenses 287 469 Selling, general and administrative expenses 627 912 $ 1,015 $ 1,513

Note 12 - Income Taxes

Note 12 - Income Taxes	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Income Tax Disclosure [Text Block]	12. For the years ended December 31, 2021 2020, zero Year Ended December 31, 2021 2020 Tax at federal statutory rate $ (3,657 ) $ (3,991 ) State taxes, net of federal benefit (711 ) (760 ) Permanent differences (445 ) 56 Change in valuation allowance 5,104 4,909 Research credits (286 ) (211 ) Other (5 ) (3 ) Provision for taxes $ — $ — Significant components of the Company’s net deferred tax assets as of December 31, 2021 2020 As of December 31, 2021 2020 Deferred tax assets: Federal, state and foreign net operating losses $ 83,211 $ 79,253 Research and other credits 4,892 4,766 Operating lease liability 752 994 Accruals and other 2,845 2,305 Total deferred tax assets 91,700 87,318 Less: Valuation allowance (90,908 ) (86,193 ) Total net deferred tax assets 792 1,125 Deferred liabilities: Fixed assets (2 ) (60 ) Operating lease right of use asset (790 ) (1,065 ) Total deferred tax liabilities (792 ) (1,125 ) Net deferred tax assets (liabilities) $ — $ — The valuation allowance increased by $4.7 million and increased by $3.4 million during the years ended December 31, 2021 2020, As of December 31, 2021, not 2027 2024, December 31, 2017 no As of December 31, 2021, 2027, not may The Company's ability to utilize the net operating loss and tax credit carryforwards in the future may 382 The Company evaluates tax positions for recognition using a more-likely-than- not 50% A reconciliation of the beginning and ending amount of the gross recognized tax benefit is as follows (in thousands): As of December 31, 2021 2020 Balance at beginning of year $ 2,307 $ 2,094 Increase based on the tax positions in the current year 228 169 (Decrease) Increase for tax positions of prior year (169 ) 44 Balance at end of year $ 2,366 $ 2,307 As of December 31, 2021, not The Company does not twelve The Company's policy is to include interest and penalties related to unrecognized tax benefits within its provision for income taxes. Due to the Company's net operating loss position, the Company has not December 31, 2021 2020. The Consolidated Appropriations Act, 2021 December 27, 2020.

Note 13 - 401(k) Plan

Note 13 - 401(k) Plan	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Retirement Benefits [Text Block]	13. 401 Plan The Company has a qualified retirement plan under section 401 may may 401 may 401

Note 14 - Subsequent Events

Note 14 - Subsequent Events	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Subsequent Events [Text Block]	14. On March 15, 2022,

Significant Accounting Policies

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation The accompanying 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 Securities and Exchange Commission (“SEC”). On March 11, 2022, 1 March 14, 2022. not
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 may may
Fair Value Measurement, Policy [Policy Text Block]	Fair Value of Financial Instruments The Company has evaluated the estimated fair value of its financial instruments as of December 31, 2021 2020.
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three December 31, 2021 2020, December 31, 2021 2020.
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 December 31, 2021 2020. The Company’s accounts receivable are due from a variety of healthcare organizations in the United States and select international markets. At December 31, 2021 2020, December 31, 2021, one December 31, 2020, The Company manufactures its commercial products in-house, including the Pantheris and Ocelot family of catheters. Certain of the Company’s product components and sub-assemblies are manufactured by sole suppliers, including internally. Disruption in component or sub-assembly supply from these manufacturers or from in-house production would have a negative impact on the Company’s financial position and results of operations. The Company is subject to certain risks, including that its devices may not no not third Existing or future devices developed by the Company may may may Disruption of our supply chain capabilities due to trade restrictions, political instability, severe weather, natural disasters, public health crises such as the ongoing COVID - 19 - 19
Receivable [Policy Text Block]	Accounts Receivable Trade accounts receivable are recorded at the invoiced amount and do not not Accounts receivable allowance for doubtful accounts provision and recoveries or write-offs are summarized as follows (in thousands): 2021 2020 Beginning balance $ 19 $ 19 Provision 2 26 Recoveries/write-offs (15 ) (26 ) Ending balance $ 6 $ 19
Inventory, Policy [Policy Text Block]	Inventories Inventories are valued at the lower of cost or net realizable value. Cost is determined using the first first not not
Property, Plant and Equipment, Policy [Policy Text Block]	Property and Equipment Property and equipment are recorded at cost. Repairs and maintenance costs are expensed as incurred. Depreciation and amortization are calculated using the straight-line method over the estimated useful lives of the assets of generally three five
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]	Impairment of Long-Lived Assets The Company reviews long-lived assets, including property and equipment, for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not not December 31, 2021.
Revenue [Policy Text Block]	Revenue Recognition The Company’s revenues are derived from ( 1 2 3 1. Lightbox console sales: Provided all other criteria for revenue recognition have been met, the Company recognizes revenue for Lightbox console sales directly to end customers when delivery and acceptance occurs, which is defined as receipt by the Company of an executed form that the installation process is complete. 2. Sales of disposables: Disposable revenues consist of sales of the Company’s catheters and accessories and are recognized when the product has shipped, risk of loss and title has passed to the customer and collectability is reasonably assured. 3. Service revenue: Service contract revenue consists of preventative maintenance, upgrades, and service contracts. Service contracts are recognized ratably over the term of the service period and maintenance contract revenue is recognized as work is performed. To date, service revenue has been insignificant. The Company offers its customers the ability to purchase or lease the Lightbox console. In addition, the Company provides a Lightbox under a limited commercial evaluation program to allow accounts to install and utilize the Lightbox for a limited trial period. When a Lightbox is placed under a lease agreement or under a commercial evaluation program, the Company retains title to the equipment and it remains capitalized on its balance sheet under property and equipment. Depreciation expense on these placed Lightboxes is recorded to cost of revenues on a straight-line basis. The costs to maintain these placed Lightboxes are charged to cost of revenues as incurred. The Company evaluates its lease and commercial evaluation program agreements and accounts for these contracts under the guidance in Accounting Standards Codification (“ASC”) 842, Leases No. 2014 09, Revenue from Contracts with Customers (Topic 606 The Company assessed whether the embedded lease is an operating lease or sales-type lease. Based on the Company’s assessment of the guidance and given that any payments under the lease agreements are dependent upon contingent future sales, it was determined that collectability of the minimum lease payments is not not For sales through distributors, the Company recognizes revenue when control of the product transfers from the Company to the distributor. The distributors are responsible for all marketing, sales, training and warranty in their respective territories. The standard terms and conditions contained in the Company’s distribution agreements do not not
Cost of Goods and Service [Policy Text Block]	Cost of Revenues Cost of revenues consists primarily of manufacturing overhead costs, material costs and direct labor. A significant portion of the Company’s cost of revenues currently consists of manufacturing overhead costs. These overhead costs include the cost of quality assurance, material procurement, inventory control, facilities, equipment and operations supervision and management. Cost of revenues also includes depreciation expense for the Lightboxes under lease and evaluation agreements, product warranty costs, product written-off due to excess or obsolescence, and certain direct costs such as shipping costs.
Standard Product Warranty, Policy [Policy Text Block]	Product Warranty Costs The Company typically offers a one 2021 2020 Beginning balance $ 193 $ 215 Warranty provision 49 142 Usage/Release (55 ) (164 ) Ending balance $ 187 $ 193
Research and Development Expense, Policy [Policy Text Block]	Research and Development The Company expenses research and development costs as incurred. Research and development expenses include personnel and personnel-related costs, costs associated with pre-clinical and clinical development activities, and costs for prototype products that are manufactured prior to market approval for that prototype product, and internal and external costs associated with the Company’s regulatory compliance, including the costs of outside consultants and contractors that assist in the process of submitting and maintaining regulatory filings, and overhead costs, including allocated facility and related expenses.
Clinical Trials [Policy Text Block]	Clinical Trials The Company accrues and expenses costs for its clinical trial activities performed by third
Share-based Payment Arrangement [Policy Text Block]	Stock-Based Compensation Stock-based compensation for the Company includes amortization related to all stock options, restricted stock units (“RSU”), based on the grant-date estimated fair value. The fair value of stock options is estimated on the date of grant using the Black-Scholes option pricing model and recognized as expense on a straight-line basis over the vesting period of the award. The Company has not 2017. No. 2016‑09, Compensation-Stock Compensation (Topic 718
Foreign Currency Transactions and Translations Policy [Policy Text Block]	Foreign Currency The Company records net gains and losses resulting from foreign exchange transactions as a component of foreign currency exchange losses in other income, net. During the years ended December 31, 2021 2020,
Income Tax, Policy [Policy Text Block]	Income Taxes The Company utilizes the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on differences between financial reporting and tax reporting bases of assets and liabilities and are measured using enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. The Company’s policy is to record interest and penalties on uncertain tax positions as income tax expense when they occur. During the years ended December 31, 2021 2020, not
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 attributable 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 attributable to common stockholder 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 December 31, 2021 2020, Net loss per share attributable to common stockholders was determined as follows (in thousands, except per share data): Year Ended December 31, 2021 2020 Net loss applicable to common stockholders $ (21,587 ) $ (22,872 ) Weighted average common stock outstanding, basic and diluted 4,722 2,462 Net loss per share attributable to common stockholders, basic and diluted $ (4.57 ) $ (9.29 ) 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: Year Ended December 31, 2021 2020 Common stock warrants equivalents 135,430 137,700 Common stock options 335 351 Convertible preferred stock 52,289 48,503 Unvested restricted stock units 17,793 35,971 205,847 222,525
Comprehensive Income, Policy [Policy Text Block]	Comprehensive Loss For the years ended December 31, 2021 2020, no
Segment Reporting, Policy [Policy Text Block]	Segment and Geographical Information The Company operates and manages its business as one December 31, 2021 2020,
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements Recently adopted accounting standards In December 2019, 2019 12, Income Taxes (Topic 740 January 1, 2021. not Recent accounting standards not In August 2020, 2020 06, Debt Debt with Conversion and Other Options (Subtopic 470 20 Contracts in Entity s Own Equity (Subtopic 815 40 s Own Equity not 815 first 2024 not In May 2021, No. 2021 04, Issuer s Accounting for Certain Modifications of Exchanges of Freestanding Equity-Classified Written Call Options January 1, 2022 not

Financial Statements Schedules

Financial Statements Schedules (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Valuation Allowances and Reserves [Table Text Block]	Convertible Preferred Stock Common Stock Total Shares Amount Shares Amount Additional Paid- In Capital Accumulated Deficit Stockholders Equity Balance at December 31, 2019 48,503 $ — 518,233 $ 10 $ 355,220 $ (348,335 ) $ 6,895 Issuance of common stock in public offerings, net of commissions and issuance costs — — 3,707,016 74 23,572 — 23,646 Employee stock-based compensation — — — — 1,513 — 1,513 Issuance of common stock under officers and directors purchase plan and vesting of restricted stock units — — 21,059 1 27 — 28 Issuance of Series A preferred stock to pay dividends 3,866 — — — 3,866 — 3,866 Accretion of Series A preferred stock dividends — — — — (3,866 ) — (3,866 ) Net and comprehensive loss — — — — — (19,006 ) (19,006 ) Balance at December 31, 2020 52,369 — 4,246,308 85 380,332 (367,341 ) 13,076 Issuance of common stock in public offerings, net of commissions and issuance costs — — 500,000 10 13,033 — 13,043 Conversion of Series B preferred stock into common stock (93 ) — 18,600 — — — — Issuance of common stock upon vesting of restricted stock units — — 13,355 1 — — 1 Employee stock-based compensation — — — — 1,015 — 1,015 Issuance of Series A preferred stock to pay dividends 4,175 — — — 4,175 — 4,175 Accretion of Series A preferred stock dividends — — — — (4,175 ) — (4,175 ) Net and comprehensive loss — — — — — (17,412 ) (17,412 ) Balance at December 31, 2021 56,451 $ — 4,778,263 $ 96 $ 394,380 $ (384,753 ) $ 9,723 Year Ended December 31, 2021 2020 Cash flows from operating activities Net loss $ (17,412 ) $ (19,006 ) Adjustments to reconcile net loss to net cash used in operating activities: Depreciation and amortization 687 897 Amortization of debt issuance costs and debt discount 86 168 Stock-based compensation 1,015 1,513 Noncash interest expense and other charges 1,564 1,524 Change in right of use asset 133 169 Provision for excess and obsolete inventories 125 528 Gain on extinguishment of debt (2,353 ) — Other non-cash charges 2 (54 ) Changes in operating assets and liabilities: Accounts receivable 89 (1 ) Inventories (849 ) (490 ) Prepaid expenses and other current assets 50 (48 ) Other assets (43 ) 5 Accounts payable 679 31 Accrued compensation (94 ) (79 ) Accrued expenses and other current liabilities 49 15 Other long-term liabilities 575 (7 ) Net cash used in operating activities (15,697 ) (14,835 ) Cash flows from investing activities Purchase of property and equipment (34 ) — Proceeds from sale of property and equipment — 65 Net cash provided by (used in) investing activities (34 ) 65 Cash flows from financing activities Proceeds from the issuance of common stock in public offerings, net of commissions and issuance costs 13,043 23,646 Proceeds from borrowings, net of issuance costs — 2,330 Proceeds from issuance of common stock under officers’ and directors’ purchase plan — 36 Net cash provided by financing activities 13,043 26,012 Net change in cash and cash equivalents (2,688 ) 11,242 Cash and cash equivalents, beginning of period 22,185 10,943 Cash and cash equivalents, end of period $ 19,497 $ 22,185 Supplemental disclosure of cash flow information Noncash investing and financing activities: Accretion of Series A preferred stock dividends $ 4,175 $ 3,866 Issuance of Series A preferred stock as dividend payment $ 4,175 $ 3,866 Reclassification of right of use asset to prepaid rent $ (133 ) $ (169 ) Purchases of property and equipment in accounts payable $ 21 $ —

Note 2 - Summary of Significa_2

Note 2 - Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Accounts Receivable, Allowance for Credit Loss [Table Text Block]	2021 2020 Beginning balance $ 19 $ 19 Provision 2 26 Recoveries/write-offs (15 ) (26 ) Ending balance $ 6 $ 19
Schedule of Product Warranty Liability [Table Text Block]	2021 2020 Beginning balance $ 193 $ 215 Warranty provision 49 142 Usage/Release (55 ) (164 ) Ending balance $ 187 $ 193
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Year Ended December 31, 2021 2020 Net loss applicable to common stockholders $ (21,587 ) $ (22,872 ) Weighted average common stock outstanding, basic and diluted 4,722 2,462 Net loss per share attributable to common stockholders, basic and diluted $ (4.57 ) $ (9.29 )
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	Year Ended December 31, 2021 2020 Common stock warrants equivalents 135,430 137,700 Common stock options 335 351 Convertible preferred stock 52,289 48,503 Unvested restricted stock units 17,793 35,971 205,847 222,525

Note 4 - Inventories (Tables)

Note 4 - Inventories (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Schedule of Inventory, Current [Table Text Block]	December 31, 2021 2020 Raw materials $ 2,503 $ 1,904 Work-in-process 1 180 Finished products 2,097 1,792 Total inventories $ 4,601 $ 3,876

Note 5 - Property and Equipme_2

Note 5 - Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Property, Plant and Equipment [Table Text Block]	December 31, 2021 2020 Equipment held by customers $ 2,362 $ 2,746 Machinery and equipment 1,391 1,679 Computer software 122 122 Computer equipment 173 144 Furniture and fixture 78 78 Leasehold improvements 320 311 Total property and equipment, gross 4,446 5,080 Less: Accumulated depreciation and amortization (4,351 ) (4,353 ) Total property and equipment, net $ 95 $ 727

Note 6 - Accrued Expenses and_2

Note 6 - Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Schedule of Accrued Liabilities [Table Text Block]	December 31, 2021 2020 Accrued product warranty costs $ 187 $ 193 Accrued clinical trial costs 153 96 Deferred revenue 123 28 Accrued travel expenses 118 104 Accrued sales and use tax 33 43 Accrued professional fees — 65 Other accrued liabilities 104 140 Total accrued expenses and other current liabilities $ 718 $ 669

Note 7 - Borrowings (Tables)

Note 7 - Borrowings (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Schedule of Debt [Table Text Block]	Year Ending December 31, 2022 $ — 2023 — 2024 9,045 2025 10,339 Total 19,384 Less: Amount of PIK additions and final facility fee to be incurred subsequent to December 31, 2021 (6,765 ) Less: Amount representing debt issuance costs (332 ) Borrowings, long term portion, as of December 31, 2021 $ 12,287

Note 8 - Leases (Tables)

Note 8 - Leases (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	Year Ending December 31, 2022 $ 1,162 2023 1,203 2024 1,138 Total 3,503 Less: Imputed interest (324 ) Leasehold liability as of December 31, 2021 $ 3,179
Right of Use Asset and Liabilities [Table Text Block]	Lease-Related Assets and Liabilities Financial Statement Line Items December 31, 2021 December 31, 2020 Right of use assets: Operating lease Right of use asset $ 3,179 $ 4,063 Total right of use assets $ 3,179 $ 4,063 Lease liabilities: Operating lease Leasehold liability, current portion $ 985 $ 806 Leasehold liability, long-term portion 2,194 3,257 Total lease liabilities $ 3,179 $ 4,063

Note 10 - Stockholders' Equity

Note 10 - Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2021
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 44,895 $ 400.00 February 2025 Series 2 Warrants issued in the February 2018 Series B financing 8,709,500 43,548 $ 400.00 February 2025 Warrants issued in the November 2018 financing 8,768,395 43,842 $ 80.00 November 2023 Placement agent warrants issued in the January 2022 financing 1,330,000 66,500 $ 10.00 January 2027 Warrants issued in the January 2022 financing 16,150,000 807,500 $ 9.60 September 2027 Total 43,936,895 1,006,285 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 44,895 $ 400.00 February 2025 Series 2 Warrants issued in the February 2018 Series B financing 8,709,500 43,548 $ 400.00 February 2025 Warrants issued in the July 2018 financing 1,083,091 5,416 $ 316.00 July 2021 Warrants issued in the November 2018 financing 8,768,395 43,842 $ 80.00 November 2023 Total 27,539,986 137,701
Share-based Payment Arrangement, Option, Activity [Table Text Block]	Number of Shares (in thousands) Weighted Average Exercise Price Weighted Average Remaining Contractual Life (in years) Intrinsic Value (in thousands) Balance at December 31, 2019 370 $ 26,189.40 $ — Options expired (28 ) $ 42,583.40 Options forfeited (1 ) $ 16,400.00 Balance at December 31, 2020 341 $ 24,831.70 5.81 $ — Options expired (10 ) $ 58,632.36 Options forfeited — $ — Balance at December 31, 2021 331 $ 23,815.95 4.93 $ — Exercisable at December 31, 2021 331 $ 23,815.95 4.93 $ — Vested and expected to vest at December 31, 2021 331 $ 23,815.95 4.93 $ —
Share-based Payment Arrangement, Option, Exercise Price Range [Table Text Block]	Options Outstanding Options Vested Weighted Weighted Weighted Average Average Average Exercise Options Remaining Exercise Number Exercise Price Outstanding Contractual Life Price Exercisable Price $ 334.00 155 6.44 $ 334.00 155 $ 334.00 $ 400.00 - 29,400.00 39 5.18 $ 17,372.31 39 $ 17,372.31 $ 36,000.00 110 3.00 $ 36,000.00 110 $ 36,000.00 $ 87,280.00 - 162,000.00 27 3.69 $ 115,913.85 27 $ 115,913.85 331 4.93 $ 23,342.58 331 $ 23,342.58
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, 2019 45,425 $ 81.80 1.81 Awarded 2,375 $ 11.60 Released (18,407 ) $ 91.40 Forfeited (8,761 ) $ 54.40 Awards outstanding at December 31, 2020 20,632 $ 76.82 0.98 Awarded 4,500 $ 32.20 Released (13,355 ) $ 104.23 Forfeited (1,727 ) $ 53.79 Awards outstanding at December 31, 2021 10,050 $ 24.37 0.72

Note 11 - Stock-based Compens_2

Note 11 - Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]	Year Ended December 31, 2021 2020 Cost of revenues $ 101 $ 132 Research and development expenses 287 469 Selling, general and administrative expenses 627 912 $ 1,015 $ 1,513

Note 12 - Income Taxes (Tables)

Note 12 - Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	Year Ended December 31, 2021 2020 Tax at federal statutory rate $ (3,657 ) $ (3,991 ) State taxes, net of federal benefit (711 ) (760 ) Permanent differences (445 ) 56 Change in valuation allowance 5,104 4,909 Research credits (286 ) (211 ) Other (5 ) (3 ) Provision for taxes $ — $ —
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	As of December 31, 2021 2020 Deferred tax assets: Federal, state and foreign net operating losses $ 83,211 $ 79,253 Research and other credits 4,892 4,766 Operating lease liability 752 994 Accruals and other 2,845 2,305 Total deferred tax assets 91,700 87,318 Less: Valuation allowance (90,908 ) (86,193 ) Total net deferred tax assets 792 1,125 Deferred liabilities: Fixed assets (2 ) (60 ) Operating lease right of use asset (790 ) (1,065 ) Total deferred tax liabilities (792 ) (1,125 ) Net deferred tax assets (liabilities) $ — $ —
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]	As of December 31, 2021 2020 Balance at beginning of year $ 2,307 $ 2,094 Increase based on the tax positions in the current year 228 169 (Decrease) Increase for tax positions of prior year (169 ) 44 Balance at end of year $ 2,366 $ 2,307

Financial Statements Schedule_2

Financial Statements Schedules - Allowance of Doubtful Accounts and Sales Returns (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
Balance at Beginning of Year	$ 19	$ 19
Charged to costs and expenses, additions	2	26
Write offs	15	26
Balance at End of Year	6	19
SEC Schedule, 12-09, Allowance, Sales Returns [Member]
Balance at Beginning of Year	20	6
Charged to costs and expenses, additions	10	29
Write offs	10	15
Balance at End of Year	$ 20	$ 20

Note 1 - Organization (Details

Note 1 - Organization (Details Textual) $ / shares in Units, $ in Thousands

Mar. 11, 2022

Mar. 01, 2022

Jan. 14, 2022USD ($)$ / sharesshares

Feb. 02, 2021USD ($)$ / sharesshares

Sep. 01, 2020USD ($)shares

Aug. 25, 2020$ / sharesshares

Aug. 11, 2020USD ($)shares

Aug. 06, 2020$ / sharesshares

Jul. 09, 2020USD ($)

Jul. 09, 2020USD ($)shares

Jun. 26, 2020$ / sharesshares

May 06, 2020USD ($)$ / sharesshares

Apr. 30, 2020$ / sharesshares

Apr. 23, 2020USD ($)

Jan. 31, 2020USD ($)$ / shares

Jan. 31, 2022USD ($)

Feb. 28, 2021USD ($)

Jan. 31, 2020USD ($)$ / sharesshares

Sep. 30, 2020USD ($)

Jul. 31, 2020USD ($)

May 31, 2020USD ($)

Jun. 30, 2020

Dec. 31, 2021USD ($)$ / sharesshares

Dec. 31, 2020USD ($)shares

Retained Earnings (Accumulated Deficit), Ending Balance | $

$ (384,753)

$ (367,341)

Cash and Cash Equivalents, at Carrying Value, Ending Balance | $

$ 19,497

$ 22,185

Preferred Stock, Par or Stated Value Per Share (in dollars per share)

$ 0.001

Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares

1,006,285

137,701

Reverse Stock Split [Member]

Stockholders' Equity Note, Stock Split, Conversion Ratio

20

Placement agent warrants issued in the January 2022 financing [Member]

Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares

66,500

Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)

$ 10

COVID 19 [Member]

Reduction of Non-manufacturing Employees Salaries

20.00%

Reduction of Hours Worked by Manufacturing Workers, Percentage

20.00%

Paycheck Protection Program CARES Act [Member]

Proceeds from Issuance of Long-term Debt, Total | $

$ 2,300

Subsequent Event [Member] | Reverse Stock Split [Member]

Stockholders' Equity Note, Stock Split, Conversion Ratio

20

Subsequent Event [Member] | Reverse Stock Split [Member] | Minimum [Member]

Stockholders' Equity Note, Stock Split, Conversion Ratio

5

5

Subsequent Event [Member] | Reverse Stock Split [Member] | Maximum [Member]

Stockholders' Equity Note, Stock Split, Conversion Ratio

20

Subsequent Event [Member] | Common Warrants [Member]

Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares

807,500

Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)

$ 9.60

Warrants and Rights Outstanding, Term (Year)

5 years

Subsequent Event [Member] | Placement agent warrants issued in the January 2022 financing [Member]

Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares

66,500

Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)

$ 10

Warrants and Rights Outstanding, Term (Year)

5 years

Subsequent Event [Member] | Series D Preferred Stock [Member]

Preferred Stock, Par or Stated Value Per Share (in dollars per share)

$ 0.001

Subsequent Event [Member] | Series D Preferred Stock [Member] | Common Warrants [Member]

Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)

$ 9.60

Warrants and Rights Outstanding, Term (Year)

5 years

Subsequent Event [Member] | Series D Preferred Stock [Member] | Placement agent warrants issued in the January 2022 financing [Member]

Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares

66,500

Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)

$ 10

Warrants and Rights Outstanding, Term (Year)

5 years

January 2022 Public Offering [Member] | Subsequent Event [Member]

Proceeds from Issuance or Sale of Equity, Net | $

$ 6,700

$ 6,700

January 2022 Public Offering [Member] | Subsequent Event [Member] | Series D Preferred Stock [Member]

Stock Issued During Period, Shares, New Issues (in shares) | shares

7,600

Shares Issued, Price Per Share (in dollars per share)

$ 1,000

Preferred Stock, Voting Rights Per Share (in dollars per share)

37,500

Preferred Stock, Convertible, Conversion Price (in dollars per share)

$ 8

January 2020 Public Offering [Member]

Proceeds from Issuance or Sale of Equity, Net | $

$ 3,900

$ 3,900

Stock Issued During Period, Shares, New Issues (in shares) | shares

321,429

Shares Issued, Price Per Share (in dollars per share)

$ 14

$ 14

April and May 2020 Public Offering [Member]

Proceeds from Issuance or Sale of Equity, Net | $

$ 3,000

June and July 2020 Public Offering [Member]

Proceeds from Issuance or Sale of Equity, Net | $

$ 5,500

August and September 2020 Public Offering [Member]

Proceeds from Issuance or Sale of Equity, Net | $

$ 11,300

February 2021 Public Offering [Member]

Proceeds from Issuance or Sale of Equity, Net | $

$ 13,000

$ 13,000

Stock Issued During Period, Shares, New Issues (in shares) | shares

500,000

Shares Issued, Price Per Share (in dollars per share)

$ 28.80

April 2020 Public Offering [Member]

Stock Issued During Period, Shares, New Issues (in shares) | shares

630,000

Shares Issued, Price Per Share (in dollars per share)

$ 5

May 2020 Public Offering [Member]

Proceeds from Issuance or Sale of Equity, Net | $

$ 3,000

Stock Issued During Period, Shares, New Issues (in shares) | shares

94,500

Shares Issued, Price Per Share (in dollars per share)

$ 5

June 2020 Public Offering [Member]

Stock Issued During Period, Shares, New Issues (in shares) | shares

1,000,000

Shares Issued, Price Per Share (in dollars per share)

$ 5.40

July 2020 Public Offering [Member]

Proceeds from Issuance or Sale of Equity, Net | $

$ 5,500

$ 700

Stock Issued During Period, Shares, New Issues (in shares) | shares

150,000

August 2020 Public Offering [Member]

Proceeds from Issuance or Sale of Equity, Net | $

$ 6,200

Stock Issued During Period, Shares, New Issues (in shares) | shares

553,192

118,421

789,474

Shares Issued, Price Per Share (in dollars per share)

$ 9.40

$ 7.60

September 2020 Public Offering [Member]

Proceeds from Issuance or Sale of Equity, Net | $

$ 5,100

Stock Issued During Period, Shares, New Issues (in shares) | shares

50,000

Note 2 - Summary of Significa_3

Note 2 - Summary of Significant Accounting Policies (Details Textual) shares in Thousands	Mar. 11, 2022	Dec. 31, 2021USD ($)shares	Dec. 31, 2020USD ($)shares
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax, Total		$ 0	$ 0
Warranty Period (Year)		1 year
Foreign Currency Transaction Gain (Loss), before Tax, Total		$ 16,000	18,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense, Total		$ 0	$ 0
Weighted Average Number of Shares, Common Stock Subject to Repurchase or Cancellation (in shares) | shares		0	0
Number of Reportable Segments		1
Minimum [Member]
Property, Plant and Equipment, Useful Life (Year)		3 years
Maximum [Member]
Property, Plant and Equipment, Useful Life (Year)		5 years
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		21.00%	14.00%
Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Number of Major Customers		1	0
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | UNITED STATES
Concentration Risk, Percentage		94.00%	94.00%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | One Customer [Member]
Concentration Risk, Percentage		10.00%
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Zero Customer [Member]
Concentration Risk, Percentage			10.00%
Reverse Stock Split [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	20

Note 2 - Summary of Significa_4

Note 2 - Summary of Significant Accounting Policies - Accounts Receivable, Allowance for Credit Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Beginning balance	$ 19	$ 19
Provision	2	26
Recoveries/write-offs	(15)	(26)
Ending balance	$ 6	$ 19

Note 2 - Summary of Significa_5

Note 2 - Summary of Significant Accounting Policies - Product Warranty (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Beginning balance	$ 193	$ 215
Warranty provision	49	142
Usage/Release	(55)	(164)
Ending balance	$ 187	$ 193

Note 2 - Summary of Significa_6

Note 2 - Summary of Significant Accounting Policies - Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Net loss applicable to common stockholders	$ (21,587)	$ (22,872)
Weighted average common stock outstanding, basic and diluted (in shares)	4,722	2,462
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (4.57)	$ (9.29)

Note 2 - Summary of Significa_7

Note 2 - Summary of Significant Accounting Policies - Anti-dilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Antidilutive Securities (in shares)	205,847	222,525
Common Stock Warrants [Member]
Antidilutive Securities (in shares)	135,430	137,700
Common Stock Options [ member]
Antidilutive Securities (in shares)	335	351
Preferred Stock [Member]
Antidilutive Securities (in shares)	52,289	48,503
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities (in shares)	17,793	35,971

Note 3 - Fair Value Measureme_2

Note 3 - Fair Value Measurements (Details Textual) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure	$ 0
Financial and Nonfinancial Liabilities, Fair Value Disclosure		$ 0
Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure		$ 0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	$ 0

Note 4 - Inventories - Schedule

Note 4 - Inventories - Schedule of Inventory (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Raw materials	$ 2,503	$ 1,904
Work-in-process	1	180
Finished products	2,097	1,792
Total inventories	$ 4,601	$ 3,876

Note 5 - Property and Equipme_3

Note 5 - Property and Equipment, Net (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Depreciation, Total	$ 687,000	$ 897,000
Property, Plant, and Equipment, Lessor Asset under Operating Lease, after Accumulated Depreciation, Total		518,000
Leased Equipment [Member]
Cost, Depreciation	$ 539,000	$ 629,000

Note 5 - Property and Equipme_4

Note 5 - Property and Equipment, Net - Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property and Equipment	$ 4,446	$ 5,080
Less: Accumulated depreciation and amortization	(4,351)	(4,353)
Total property and equipment, net	95	727
Equipment Held by Customers [Member]
Property and Equipment	2,362	2,746
Machinery and Equipment [Member]
Property and Equipment	1,391	1,679
Software Development [Member]
Property and Equipment	122	122
Computer Equipment [Member]
Property and Equipment	173	144
Furniture and Fixtures [Member]
Property and Equipment	78	78
Leasehold Improvements [Member]
Property and Equipment	$ 320	$ 311

Note 6 - Accrued Expenses and_3

Note 6 - Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accrued product warranty costs	$ 187	$ 193
Accrued clinical trial costs	153	96
Deferred revenue	123	28
Accrued travel expenses	118	104
Accrued sales and use tax	33	43
Accrued professional fees	0	65
Other accrued liabilities	104	140
Total accrued expenses and other current liabilities	$ 718	$ 669

Note 7 - Borrowings (Details Te

Note 7 - Borrowings (Details Textual) - USD ($)	Jan. 22, 2021	Apr. 23, 2020	Feb. 14, 2018	Apr. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Apr. 17, 2021	Mar. 02, 2020	Jun. 15, 2016	Sep. 22, 2015
Interest Expense, Total					$ 1,651,000	$ 1,692,000
Gain (Loss) on Extinguishment of Debt, Total					2,353,000	0
Paycheck Protection Program CARES Act [Member]
Interest Expense, Total					7,000	16,000
Proceeds from Issuance of Long-term Debt, Total		$ 2,300,000
Long-term Debt, Total							$ 0
Debt Instrument Interest Forgiven				$ 23,000
Paycheck Protection Program CARES Act [Member] | Other Nonoperating Income (Expense) [Member]
Gain (Loss) on Extinguishment of Debt, Total				$ 2,400,000
CRG [Member] | Loan Agreement [Member]
Debt Agreement, Maximum Borrowing Capacity										$ 50,000,000
Debt Instrument, Covenant Compliance Target Minimum Revenue, Next Twelve Months	$ 8,000,000							$ 10,000,000
Debt Instrument, Covenant, Compliance Target Minimum Revenue Second Year	10,000,000							12,000,000
Debt Instrument, Covenant Compliance Target Minimum Revenue Third Year	12,000,000							$ 15,000,000
Debt Instrument, Covenant Compliance Target Minimum Revenue Fourth Year	14,500,000
Debt Instrument, Covenant Compliance Target Minimum Revenue Fifth Year	$ 17,000,000
Debt Instrument, Interest Rate, Stated Percentage	12.50%
Debt Instrument, Periodic Payment, Total	$ 1,900,000
Long-Term Debt, Maturity, Year Four	7,500,000
Long-Term Debt, Maturity, Year Five	$ 7,500,000
Debt Instrument, Redemption Initial Prepayment Premium Percentage	5.00%
Debt Instrument, Redemption Annual Decline in Prepayment Premium Percentage	1.00%
Debt Instrument, Redemption Prepayment Premium Percentage after Fifth Year	0.00%
Debt Instrument, Financing Fee Percentage	1.50%
Debt Instrument, Final Facility Fee Percentage	15.00%
Debt Instrument, Covenant Compliance Cash and Certain Cash Equivalents Minimum	$ 3,500,000
Debt Instrument, Covenant Compliance Prepayment Multiplier for Revenue Shortfall	2
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net, Total					333,000	418,000				1,300,000
Amortization of Debt Discount (Premium)					86,000	169,000
Interest Expense, Total					$ 1,600,000	$ 1,500,000
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

Note 7 - Borrowings - Schedule

Note 7 - Borrowings - Schedule of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Borrowings, long term portion, as of December 31, 2021	$ 0	$ 3,590
CRG [Member] | Loan Agreement [Member]
2022	0
2023	0
2024	9,045
Long-Term Debt, Maturity, Year Four	10,339
Total	19,384
Less: Amount of PIK additions and final facility fee to be incurred subsequent to December 31, 2021	(6,765)
Less: Amount representing debt issuance costs	(332)
Borrowings, long term portion, as of December 31, 2021	$ 12,287

Note 8 - Leases (Details Textua

Note 8 - Leases (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Apr. 01, 2019
Lessee, Operating Lease, Liability, Payments, Due, Total	$ 3,503,000		$ 5,800,000
Operating Lease, Weighted Average Remaining Lease Term (Year)	2 years 10 months 24 days
Lessee, Operating Lease, Discount Rate	6.50%
Operating Lease, Expense, Excluding Maintenance Fee and Other Expense, Monthly	$ 105,000	$ 105,000
Operating Lease, Expense	1,300,000	1,300,000
Variable Lease, Cost	200,000	200,000
Operating Lease, Right-of-Use Asset, Amortization Expense	1,000,000	964,000
Prepaid Rent	$ 158,000	$ 291,000

Note 8 - Leases - Future Operat

Note 8 - Leases - Future Operating Lease Payments (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Apr. 01, 2019
2022	$ 1,162
2023	1,203
2024	1,138
Total	3,503		$ 5,800
Less: Imputed interest	(324)
Leasehold liability as of December 31, 2021	$ 3,179	$ 4,063

Note 8 - ROU Assets and Lease L

Note 8 - ROU Assets and Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Operating lease	$ 3,179	$ 4,063
Total right of use assets	3,179	4,063
Operating lease	985	806
Operating Lease, Liability, Noncurrent	2,194	3,257
Total lease liabilities	$ 3,179	$ 4,063

Note 9 - Commitments and Cont_2

Note 9 - Commitments and Contingencies (Details Textual) $ in Millions	Dec. 31, 2021USD ($)
Purchase Commitment [Member]
Purchase Obligation, Total	$ 1.4

Note 10 - Stockholders' Equit_2

Note 10 - Stockholders' Equity (Details Textual)	Mar. 11, 2022	Mar. 01, 2022	Jan. 14, 2022$ / sharesshares	Feb. 14, 2018	Dec. 31, 2021USD ($)$ / sharesshares	Dec. 31, 2020USD ($)shares	Mar. 15, 2022shares	Mar. 10, 2020shares	Aug. 28, 2019shares	Aug. 22, 2018shares	Feb. 16, 2018$ / shares	Jan. 31, 2015
Preferred Stock, Shares Authorized (in shares)					5,000,000
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares					$ 0.001
Preferred Stock, Shares Issued, Total (in shares)					56,451	52,369
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)					1,006,285	137,701
Common Stock, Shares Authorized (in shares)					100,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares					$ 0.001
Common Stock, Shares, Issued, Total (in shares)					4,778,263
Class Of Warrant Or Right Warrants Expired (in shares)					1,083,091
Class of Warrant or Right, Number of Securities Called By Warrants or Rights Expired (in shares)					5,416
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)					4 years
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)					10 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)					0	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)					0	0
Share-based Payment Arrangement, Expense | $					$ 1,015,000	$ 1,513,000
Share Price (in dollars per share) | $ / shares					$ 9
Share-based Payment Arrangement, Option [Member]
Share-based Payment Arrangement, Expense | $					$ 4,000	58,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total | $					0
Share-based Payment Arrangement, Expense, Tax Benefit | $					0	0
Restricted Stock Units (RSUs) [Member]
Share-based Payment Arrangement, Expense | $					1,000,000	1,500,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total | $					$ 200,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)					1 year
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Fair Value | $						100,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value | $					$ 273,000	$ 135,000
The 2015 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Additional Shares Reserved for Issuance, Percentage on Shares Outstanding												5.00%
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)					8,480
Officer and Director Share Purchase Plan [Member]
Common Stock, Shares, Issued, Total (in shares)					0	2,652
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)					4,609
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)								6,250	2,000	1,000
Reverse Stock Split [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	20
Minimum [Member] | Common Stock Options [ member]
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent					100.00%
Minimum [Member] | Common Stock Options [ member] | Stockholder with More than 10% Voting Power [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent					110.00%
Minimum [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)					3 years
Placement agent warrants issued in the January 2022 financing [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)					66,500
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares					$ 10
Subsequent Event [Member] | Reverse Stock Split [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	20
Subsequent Event [Member] | Minimum [Member] | Reverse Stock Split [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	5	5
Subsequent Event [Member] | Maximum [Member] | Reverse Stock Split [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	20
Subsequent Event [Member] | Common Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)			807,500
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares			$ 9.60
Warrants and Rights Outstanding, Term (Year)			5 years
Subsequent Event [Member] | Placement agent warrants issued in the January 2022 financing [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)			66,500
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares			$ 10
Warrants and Rights Outstanding, Term (Year)			5 years
Conversion of Series B Preferred Stock into Common Stock [Member]
Conversion of Stock, Shares Converted (in shares)					93
Conversion of Stock, Shares Issued (in shares)					18,600
Series A Preferred Stock [Member]
Preferred Stock, Shares Outstanding, Ending Balance (in shares)					56,366
Preferred Stock, Liquidation Preference Per Share (in dollars per share) | $ / shares					$ 1,000
Preferred Stock, Convertible, Conversion Price (in dollars per share) | $ / shares					$ 400
Dividends, Preferred Stock, Total | $					$ 4,200,000	$ 3,900,000
Series A Preferred Stock [Member] | CRG [Member]
Preferred Stock Dividends, Shares (in shares)					4,175	3,866
Series A Preferred Stock [Member] | Conversion of Principal Amount of Senior Secured Loan to Newly Authorized Series A Preferred Stock [Member]
Preferred Stock, Dividend Rate, Percentage				8.00%
Series B Preferred Stock [Member]
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares											$ 0.001
Preferred Stock, Shares Outstanding, Ending Balance (in shares)					85
Preferred Stock, Convertible, Conversion Price (in dollars per share) | $ / shares					$ 5
Series D Preferred Stock [Member] | Subsequent Event [Member]
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares			$ 0.001
Preferred Stock, Shares Outstanding, Ending Balance (in shares)							2,400
Preferred Stock, Convertible, Shares Issuable (in shares)							300,000
Series D Preferred Stock [Member] | Subsequent Event [Member] | Common Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares			$ 9.60
Warrants and Rights Outstanding, Term (Year)			5 years
Series D Preferred Stock [Member] | Subsequent Event [Member] | Placement agent warrants issued in the January 2022 financing [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)			66,500
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares			$ 10
Warrants and Rights Outstanding, Term (Year)			5 years
Series D Preferred Stock [Member] | January 2022 offering [Member] | Subsequent Event [Member]
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares			$ 0.001
Preferred Stock, Convertible, Conversion Price (in dollars per share) | $ / shares			$ 8
Stock Issued During Period, Shares, New Issues (in shares)			7,600
Shares Issued, Price Per Share (in dollars per share) | $ / shares			$ 1,000
Preferred Stock, Convertible, Shares Issuable (in shares)			950,000
Conversion of Preferred Stock Allowed, Maximum Ownership of Common Stock, Percentage			4.99%
Conversion of Preferred Stock Allowed, Maximum Ownership of Common Stock, Percentage upon Election			9.99%
Series D Preferred Stock [Member] | January 2022 offering [Member] | Subsequent Event [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%
Series D Preferred Stock [Member] | January 2022 Public Offering [Member] | Subsequent Event [Member]
Preferred Stock, Convertible, Conversion Price (in dollars per share) | $ / shares			$ 8
Stock Issued During Period, Shares, New Issues (in shares)			7,600
Shares Issued, Price Per Share (in dollars per share) | $ / shares			$ 1,000
Preferred Stock, Voting Rights Per Share (in dollars per share) | $ / shares			$ 37,500

Note 10 - Stockholder's Equity

Note 10 - Stockholder's Equity - Outstanding Warrants (Details) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Total outstanding and exercisable (in shares)	43,936,895	27,539,986
Underlying shares of common stock (in shares)	1,006,285	137,701
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)	44,895	44,895
Exercise price per share (in dollars per share)	$ 400	$ 400
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)	43,548	43,548
Exercise price per share (in dollars per share)	$ 400	$ 400
November 2018 Warrants [Member]
Total outstanding and exercisable (in shares)	8,768,395	8,768,395
Underlying shares of common stock (in shares)	43,842	43,842
Exercise price per share (in dollars per share)	$ 80	$ 80
July 2018 Warrants [Member]
Total outstanding and exercisable (in shares)		1,083,091
Underlying shares of common stock (in shares)		5,416
Exercise price per share (in dollars per share)		$ 316
Placement agent warrants issued in the January 2022 financing [Member]
Total outstanding and exercisable (in shares)	1,330,000
Underlying shares of common stock (in shares)	66,500
Exercise price per share (in dollars per share)	$ 10
Warrants Issued in the January 2022 Financing [Member]
Total outstanding and exercisable (in shares)	16,150,000
Underlying shares of common stock (in shares)	807,500
Exercise price per share (in dollars per share)	$ 9.60

Note 10 - Stockholders' Equit_3

Note 10 - Stockholders' Equity - Stock Option Activity (Details) - $ / shares shares in Thousands	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Options (in shares)		341	370
Options, weighted average exercise price (in dollars per share)		$ 24,831.70	$ 26,189.40
Options expired (in shares)		(10)	(28)
Options expired, weighted average exercise price (in dollars per share)		$ 58,632.36	$ 42,583.40
Options forfeited (in shares)		0	(1)
Options forfeited, weighted average exercise price (in dollars per share)		$ 0	$ 16,400
Options, weighted average remaining contractual life (Year)	5 years 9 months 21 days	4 years 11 months 4 days
Options (in shares)	341	331	341
Options, weighted average exercise price (in dollars per share)	$ 24,831.70	$ 23,815.95	$ 24,831.70
Exercisable (in shares)		331
Exercisable, weighted average exercise price (in dollars per share)		$ 23,815.95
Exercisable, weighted average remaining contractual life (Year)		4 years 11 months 4 days
Vested and expected to vest (in shares)		331
Vested and expected to vest, weighted average exercise price (in dollars per share)		$ 23,815.95
Vested and expected to vest, weighted average remaining contractual life (Year)		4 years 11 months 4 days

Note 10 - Stockholders' Equit_4

Note 10 - Stockholders' Equity - Options Outstanding and Vested (Details)	12 Months Ended
	Dec. 31, 2021$ / sharesshares
Exercise Price, Upper Limit (in dollars per share)	$ 334
Options Outstanding (in shares) | shares	155
Weighted Average Remaining Contractual Life (Year)	6 years 5 months 8 days
Weighted Average Exercise Price (in dollars per share)	$ 334
Number Exercisable (in shares) | shares	155
Weighted Average Exercise Price, options vested (in dollars per share)	$ 334
Exercise Price Range 1 [Member]
Exercise Price, Upper Limit (in dollars per share)	$ 29,400
Options Outstanding (in shares) | shares	39
Weighted Average Remaining Contractual Life (Year)	5 years 2 months 4 days
Weighted Average Exercise Price (in dollars per share)	$ 17,372.31
Number Exercisable (in shares) | shares	39
Weighted Average Exercise Price, options vested (in dollars per share)	$ 17,372.31
Exercise Price, Lower Limit (in dollars per share)	400
Exercise Price Range 2 [Member]
Exercise Price, Upper Limit (in dollars per share)	$ 36,000
Options Outstanding (in shares) | shares	110
Weighted Average Remaining Contractual Life (Year)	3 years
Weighted Average Exercise Price (in dollars per share)	$ 36,000
Number Exercisable (in shares) | shares	110
Weighted Average Exercise Price, options vested (in dollars per share)	$ 36,000
Exercise Price, Lower Limit (in dollars per share)
Exercise Price Range 3 [Member]
Exercise Price, Upper Limit (in dollars per share)	$ 162,000
Options Outstanding (in shares) | shares	27
Weighted Average Remaining Contractual Life (Year)	3 years 8 months 8 days
Weighted Average Exercise Price (in dollars per share)	$ 115,913.85
Number Exercisable (in shares) | shares	27
Weighted Average Exercise Price, options vested (in dollars per share)	$ 115,913.85
Exercise Price, Lower Limit (in dollars per share)	87,280
Exercise Price Range 4 [Member]
Exercise Price, Upper Limit (in dollars per share)
Options Outstanding (in shares) | shares	331
Weighted Average Remaining Contractual Life (Year)	4 years 11 months 4 days
Weighted Average Exercise Price (in dollars per share)	$ 23,342.58
Number Exercisable (in shares) | shares	331
Weighted Average Exercise Price, options vested (in dollars per share)	$ 23,342.58
Exercise Price, Lower Limit (in dollars per share)

Note 10 - Stockholders' Equit_5

Note 10 - Stockholders' Equity - Restricted Stock Units Award Activity (Details) - Restricted Stock Units (RSUs) [Member] - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Awards outstanding, shares (in shares)	20,632	45,425
Awards outstanding, Weighted Average Grant Date Fair Value (in dollars per share)	$ 76.82	$ 81.80
Awards outstanding, Weighted Average Remaining Contractual Term (Year)	8 months 19 days	11 months 23 days	1 year 9 months 21 days
Awarded, shares (in shares)	4,500	2,375
Awarded, Weighted Average Grant Date Fair Value (in dollars per share)	$ 32.20	$ 11.60
Released, shares (in shares)	(13,355)	(18,407)
Released, Weighted Average Grant Date Fair Value (in dollars per share)	$ 104.23	$ 91.40
Forfeited, shares (in shares)	(1,727)	(8,761)
Forfeited, , Weighted Average Grant Date Fair Value (in dollars per share)	$ 53.79	$ 54.40
Awards outstanding, shares (in shares)	10,050	20,632	45,425
Awards outstanding, Weighted Average Grant Date Fair Value (in dollars per share)	$ 24.37	$ 76.82	$ 81.80

Note 11 - Stock-based Compens_3

Note 11 - Stock-based Compensation - Noncash Stock-based Compensation Expense Related to Stock Options, ESPP, and RSUs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Allocated Share-based Compensation Expense	$ 1,015	$ 1,513
Cost of Sales [Member]
Allocated Share-based Compensation Expense	101	132
Research and Development Expense [Member]
Allocated Share-based Compensation Expense	287	469
Selling, General and Administrative Expenses [Member]
Allocated Share-based Compensation Expense	$ 627	$ 912

Note 12 - Income Taxes (Details

Note 12 - Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Expense (Benefit), Total	$ 0	$ 0
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	4,700	3,400
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total	0
State and Local Jurisdiction [Member]
Income Tax Expense (Benefit), Total	0	$ 0
Operating Loss Carryforwards, Total	204,800
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total	334,400
Operating Loss Carryforwards, Not Subject to Expiration	76,900
Domestic Tax Authority [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	$ 3,900

Note 12 - Income Taxes - Effect

Note 12 - Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Tax at federal statutory rate	$ (3,657)	$ (3,991)
State taxes, net of federal benefit	(711)	(760)
Permanent differences	(445)	56
Change in valuation allowance	5,104	4,909
Research credits	(286)	(211)
Other	(5)	(3)
Provision for taxes	$ 0	$ 0

Note 12 - Income Taxes - Deferr

Note 12 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Federal, state and foreign net operating losses	$ 83,211	$ 79,253
Research and other credits	4,892	4,766
Operating lease liability	752	994
Accruals and other	2,845	2,305
Total deferred tax assets	91,700	87,318
Less: Valuation allowance	(90,908)	(86,193)
Total net deferred tax assets	792	1,125
Fixed assets	(2)	(60)
Operating lease right of use asset	(790)	(1,065)
Total deferred tax liabilities	(792)	(1,125)
Net deferred tax assets (liabilities)	$ 0	$ 0

Note 12 - Income Taxes - Reconc

Note 12 - Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Balance	$ 2,307	$ 2,094
Increase based on the tax positions in the current year	228	169
(Decrease) Increase for tax positions of prior year	(169)
(Decrease) Increase for tax positions of prior year		44
Balance	$ 2,366	$ 2,307

Note 13 - 401(k) Plan (Details

Note 13 - 401(k) Plan (Details Textual) - Pension Plan [Member] - The 401(k) Plan [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	99.00%
Defined Contribution Plan, Cost	$ 0

Note 14 - Subsequent Events (De

Note 14 - Subsequent Events (Details Textual) - Subsequent Event [Member]	Mar. 15, 2022shares
Series D Preferred Stock [Member]
Preferred Stock, Shares Outstanding, Ending Balance (in shares)	2,400
Preferred Stock, Convertible, Shares Issuable (in shares)	300,000
Series D Preferred Stock [Member] | Series D Preferred Stock Converted into Common Stock [Member]
Conversion of Stock, Shares Converted (in shares)	5,200
Common Stock in March, 2022 [Member] | Series D Preferred Stock Converted into Common Stock [Member]
Conversion of Stock, Shares Issued (in shares)	650,000