BioCardia (BCDA) 10-K 29 Mar 22 2021 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2021	Mar. 23, 2022	Jun. 30, 2021
Document Information [Line Items]
Entity Central Index Key	0000925741
Entity Registrant Name	BioCardia, 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	0-21419
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	23-2753988
Entity Address, Address Line One	320 Soquel Way
Entity Address, City or Town	Sunnyvale
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94085
City Area Code	650
Local Phone Number	226-0120
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
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 51,800,000
Entity Common Stock, Shares Outstanding		16,871,265
Auditor Name	PKF San Diego, LLP
Auditor Location	San Diego, California
Auditor Firm ID	27
Warrant [Member]
Document Information [Line Items]
Title of 12(b) Security	Warrant to Purchase Common Stock
Trading Symbol	BCDAW
Security Exchange Name	NASDAQ
Common Stock [Member]
Document Information [Line Items]
Title of 12(b) Security	Common Stock, par value $0.001
Trading Symbol	BCDA
Security Exchange Name	NASDAQ

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 12,872	$ 21,407
Accounts receivable, net of allowance for doubtful accounts of $22 and $16 as of December 31, 2021 and 2020	147	232
Prepaid expenses and other current assets	462	401
Other receivable due from related party	0	618
Total current assets	13,481	22,658
Property and equipment, net	182	145
Operating lease right-of-use asset, net	1,883	567
Other assets	172	54
Total assets	15,718	23,424
Current liabilities:
Accounts payable	507	746
Accrued expenses and other current liabilities	2,121	2,205
Deferred revenue	847	683
Operating lease liability - current	237	614
Total current liabilities	3,712	4,248
Operating lease liability - noncurrent	1,631	0
Total liabilities	5,343	4,248
Commitments and contingencies (Notes 1,2,5 and 14)
Stockholders’ equity:
Preferred stock, $0.001 par value, 25,000,000 shares authorized as of December 31, 2021 and December 31, 2020; no shares issued and outstanding as of December 31, 2021 and 2020	0	0
Common stock, $0.001 par value, 100,000,000 shares authorized as of December 31, 2021 and 2020; 16,871,265 and 16,297,381 shares issued and outstanding as of December 31, 2021 and 2020, respectively	17	16
Additional paid-in capital	139,055	135,234
Accumulated deficit	(128,697)	(116,074)
Total stockholders’ equity	10,375	19,176
Total liabilities and stockholders’ equity	$ 15,718	$ 23,424

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Allowance for doubtful accounts	$ 22,000	$ 16,000
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	25,000,000	25,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	16,871,265	16,297,381
Common stock, shares outstanding (in shares)	16,871,265	16,297,381

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Revenue:
Total revenue	$ 1,015	$ 145
Costs and expenses:
Cost of goods sold	0	4
Research and development	8,558	9,809
Selling, general and administrative	5,087	5,861
Total costs and expenses	13,645	15,674
Operating loss	(12,630)	(15,529)
Other income (expense):
Interest income	9	21
Gain on extinguishment of Paycheck Protection Program note payable	0	509
Interest expense	0	(3)
Other expense	(2)	(2)
Total other income, net	7	525
Net loss	$ (12,623)	$ (15,004)
Net loss per share, basic and diluted (in dollars per share)	$ (0.75)	$ (1.48)
Weighted-average shares used in computing net loss per share, basic and diluted (in shares)	16,917,664	10,118,682
Product [Member]
Revenue:
Total revenue	$ 1	$ 13
Collaboration Agreement [Member]
Revenue:
Total revenue	$ 1,014	$ 132

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Public Offering [Member]Common Stock [Member]	Public Offering [Member]Additional Paid-in Capital [Member]	Public Offering [Member]Retained Earnings [Member]	Public Offering [Member]	The $8.5 Million Registered Direct Offering [Member]Common Stock [Member]	The $8.5 Million Registered Direct Offering [Member]Additional Paid-in Capital [Member]	The $8.5 Million Registered Direct Offering [Member]Retained Earnings [Member]	The $8.5 Million Registered Direct Offering [Member]	The $10.5 Million Registered Direct Offering [Member]Common Stock [Member]	The $10.5 Million Registered Direct Offering [Member]Additional Paid-in Capital [Member]	The $10.5 Million Registered Direct Offering [Member]Retained Earnings [Member]	The $10.5 Million Registered Direct Offering [Member]	Restricted Stock Units (RSUs) [Member]Management [Member]Common Stock [Member]	Restricted Stock Units (RSUs) [Member]Management [Member]Additional Paid-in Capital [Member]	Restricted Stock Units (RSUs) [Member]Management [Member]	Restricted Stock Units (RSUs) [Member]Board of Directors [Member]Common Stock [Member]	Restricted Stock Units (RSUs) [Member]Board of Directors [Member]Additional Paid-in Capital [Member]	Restricted Stock Units (RSUs) [Member]Board of Directors [Member]	Restricted Stock Units (RSUs) [Member]Common Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2019																				6,825,183
Balance at Dec. 31, 2019																				$ 7	$ 103,433	$ (101,070)	$ 2,370
Common stock issued (in shares)	5,476,190				1,789,474				2,038,836
Common stock issued	$ 5	$ 10,268	$ 0	$ 10,273	$ 2	$ 7,825	$ 0	$ 7,827	$ 2	$ 9,763	$ 0	$ 9,765
Restricted stock units issued (in shares)													71,624			39,807			26,172
Restricted stock units issued														$ 232	$ 232		$ 613	$ 613
Common stock grants to former directors to settle board compensation obligations (in shares)																				29,625
Common stock grants to former directors to settle board compensation obligations																				$ 0	148	0	148
Exercise of common stock warrants (in shares)																				470
Exercise of common stock warrants																				$ 0	0	0	0
Share-based compensation																					2,952		2,952
Net loss																						(15,004)	(15,004)
Balance (in shares) at Dec. 31, 2020																				16,297,381
Balance at Dec. 31, 2020																				$ 16	135,234	(116,074)	19,176
Common stock issued (in shares)																				453,832
Common stock issued																				$ 1	1,941	0	1,942
Restricted stock units issued (in shares)																			40,100	78,372
Restricted stock units issued														$ 214	$ 214
Share-based compensation																					1,661		1,661
Net loss																						(12,623)	$ (12,623)
Exercise of common stock options (in shares)																				1,580			1,580
Exercise of common stock options																					5		$ 5
Balance (in shares) at Dec. 31, 2021																				16,871,265
Balance at Dec. 31, 2021																				$ 17	$ 139,055	$ (128,697)	$ 10,375

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Public Offering [Member]
Issuance costs		$ 1,227
The $8.5 Million Registered Direct Offering [Member]
Issuance costs		673
The $10.5 Million Registered Direct Offering [Member]
Issuance costs		$ 735
Issuance costs	$ 59

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating activities:
Net loss	$ (12,623)	$ (15,004)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	60	68
Non-cash interest expense on convertible stockholder notes	0	3
Gain on extinguishment of Paycheck Protection Program note payable	0	(509)
Share-based compensation	1,661	2,952
Loss on disposal of property and equipment	19	0
Changes in operating assets and liabilities:
Accounts receivable	85	(85)
Inventory	0	4
Prepaid expenses and other current assets	(179)	241
Other receivable due from related party	618	(618)
Accounts payable	(239)	(168)
Accrued liabilities and other current liabilities	130	797
Deferred revenue	164	(8)
Operating lease liability - current	(618)	86
Operating lease liability - noncurrent	(24)	(614)
Right-of-use assets	580	498
Net cash used in operating activities	(10,366)	(12,357)
Investing activities:
Purchase of property and equipment	(116)	(32)
Net cash used in investing activities	(116)	(32)
Financing activities:
Proceeds from sale of common stock	2,001	0
Issuance costs of sale of common stock	(59)	(2,635)
Proceeds from Paycheck Protection Program note payable	0	506
Tax withholding payments on settlement of restricted stock unit awards	0	(160)
Proceeds from exercise of common stock options	5	0
Net cash provided by financing activities	1,947	28,211
Net change in cash and cash equivalents	(8,535)	15,822
Cash and cash equivalents at beginning of year	21,407	5,585
Cash and cash equivalents at end of year	12,872	21,407
Supplemental disclosure for noncash investing and financing activities:
Restricted stock units issued to settle management bonus obligations	393	391
Restricted stock units issued to settle board compensation obligations	0	613
Common stock grants to former directors to settle board compensation obligations	0	148
Right-of-use asset obtained in exchange for lease obligation	1,896	0
Public Offering [Member]
Financing activities:
Proceeds from sale of common stock	0	11,500
The $8.5 Million Registered Direct Offering [Member]
Financing activities:
Proceeds from sale of common stock	0	8,500
The $10.5 Million Registered Direct Offering [Member]
Financing activities:
Proceeds from sale of common stock	$ 0	$ 10,500

Note 1 - Summary of Business

Note 1 - Summary of Business	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Business Description and Basis of Presentation [Text Block]	( 1 Summary of Business (a) Organization and Description of Business BioCardia, Inc. (we, us, our, BioCardia or the Company), is a clinical-stage company focused on developing cellular and cell-derived therapeutics for the treatment of cardiovascular and pulmonary diseases with significant unmet medical needs. The Company’s lead therapeutic candidates are based on the CardiAMP Cell Therapy System, a platform which provides an autologous bone marrow derived cell therapy for treatment in two second 1 BioCardia also has three 1 2 3 The ongoing novel coronavirus (COVID- 19 19 not twelve December 31, 2021, may 19 may

Note 2 - Significant Accounting

Note 2 - Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Significant Accounting Policies [Text Block]	( 2 Significant Accounting Policies (a) Basis of Presentation and Consolidation These consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (U.S. GAAP) and include all adjustments necessary for the fair presentation of the Company’s financial position for the periods presented. The consolidated financial statements include the accounts of the Company and its wholly owned subsidiary, BioCardia Lifesciences, Inc. All material intercompany accounts and transactions have been eliminated during the consolidation process. (b) Liquidity Going Concern The Company has incurred net losses and negative cash flows from operations since our inception and had an accumulated deficit of $128.7 million as of December 31, 2021. December 31, 2021 not fourth 2022. one not The Company’s ability to continue as a going concern and to continue further development of its therapeutic candidates beyond the fourth 2022, not not may may (c) Use of Estimates The preparation of the financial statements in accordance with U.S. GAAP requires management to make certain estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ materially from those estimates. Significant items subject to such estimates and assumptions include share-based compensation, the useful lives of property and equipment, right-of-use assets and related liabilities, incremental borrowing rate, allowances for doubtful accounts and sales returns, clinical accruals and assumptions used for revenue recognition. (d) Cash Equivalents The Company classifies all highly liquid investments with an original maturity date of 90 (e) Concentration of Credit Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents. The Company maintains its cash at reputable U.S. financial institutions, which at times, exceed federally insured limits of $250,000 December 31, 2021, one not not (f) Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable are recorded at the invoiced amount and do not not December 31, 2021 2020, (g) Property and Equipment, Net Property and equipment, net, are carried at cost less accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the related assets, as described in the table below. Maintenance and repairs are expensed as incurred. When assets are retired or otherwise disposed of, the cost and the related accumulated depreciation and amortization are removed from the accounts and any resulting gain or loss is reflected in the accompanying consolidated statements of operations. Asset Estimated useful lives (in years) Computer equipment and software 3 Laboratory and manufacturing equipment 3 Furniture and fixtures 3 Leasehold improvements 5 years or lease term, if shorter (h) Right-of-Use Assets Operating lease right-of-use asset and liabilities 12 The Company’s lease liabilities are recognized at the applicable lease commencement date based on the present value of the lease payments required to be paid over the lease term. Variable lease payments are expensed as incurred and are not The Company's ROU assets are also recognized at the applicable lease commencement date. The ROU asset equals the carrying amount of the related lease liability, adjusted for any lease payments made prior to lease commencement and lease incentives provided by the lessor, if any. The Company reduces a ROU asset, and the periodic reduction is the difference between the straight-line total lease cost for the period (including reduction of initial direct costs) and the periodic accretion of the lease liability using the effective interest method. The Company’s lease terms may The Company’s lease contracts often include lease and non-lease components. The Company has elected the practical expedient offered by the standard to not The Company has elected not twelve (i) Long-lived Assets Impairment assessment of long-lived assets may not December 31, 2021, (j) Clinical Trial Accruals As part of the process of preparing its consolidated financial statements, the Company is required to estimate its expenses resulting from its obligations under contracts with vendors and consultants and clinical site agreements in connection with conducting clinical trials. The financial terms of these contracts are subject to negotiation and may not not may may (k) Revenue Recognition Net product revenue Collaboration agreement revenue In determining the appropriate amount of revenue to be recognized as it fulfills its obligations under each of its agreements, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations, including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. As part of the accounting for these arrangements, the Company must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. The Company uses key assumptions to determine the stand-alone selling price, which may not The Company applies judgment in determining whether a combined performance obligation is satisfied at a point in time or over time, and, if over time, concluding upon the appropriate method of measuring progress to be applied for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, as estimates related to the measure of progress change, related revenue recognition is adjusted accordingly. Changes in the Company’s estimated measure of progress are accounted for prospectively as a change in accounting estimate. The Company recognizes collaboration revenue by measuring the progress toward complete satisfaction of the performance obligation using an input measure. The Company will re-evaluate the estimate of expected costs to satisfy the performance obligation each reporting period and make adjustments for any significant changes. Amounts received prior to satisfying the revenue recognition criteria are recorded as deferred revenue in the Company’s consolidated balance sheets. If the related performance obligation is expected to be satisfied within the next twelve may not one December 31, 2021 2020, Multiple contracts with the same customer - two one one Contract costs - one not Contract modifications - one not not not (l) Product Warranties The Company provides a standard warranty of serviceability on all its products for the duration of the product’s shelf life, which is two not December 31, 2021 2020. (m) Research and Development The Company’s research and development costs are expensed as incurred. Research and development expense include the costs of basic research activities as well as other research, engineering, and technical effort required to develop new products or services or make significant improvement to an existing product or manufacturing process. Research and development costs also include pre-approval regulatory and clinical trial expenses and support costs for collaborative partnering programs wherein the Company provides biotherapeutic delivery systems and customer training and support for their use in clinical trials and studies. The Company’s research and development costs consist primarily of: • Salaries, benefits and other personnel-related expenses, including share-based compensation; • Fees paid for services provided by clinical research organizations, research institutions, consultants and other outside service providers; • Costs to acquire and manufacture materials used in research and development activities and clinical trials; • Laboratory consumables and supplies; • Facility-related expenses allocated to research and development activities; • Fees to collaborators to license technology; and • Depreciation expense for equipment used for research and development and clinical purposes. (n) Share-Based Compensation The Company measures and recognizes share-based compensation expense for equity awards to employees, directors and consultants based on fair value at the grant date. The Company uses the Black-Scholes-Merton (BSM) option pricing model to calculate fair value of its stock option grants. The compensation cost for restricted stock awards is based on the closing price of the Company’s common stock on the date of grant. Share-based compensation expense recognized in the consolidated statements of operations is based on the period the services are performed and recognized as compensation expense on a straight-line basis over the requisite service period. The Company accounts for forfeitures as they occur. Measurement of nonemployee awards - The measurement of equity-classified nonemployee awards is fixed at the grant date, and the Company may 505 50 The BSM option pricing model requires the input of subjective assumptions, including the risk-free interest rate, the expected volatility in the value of the Company’s common stock, and the expected term of the option. These estimates involve inherent uncertainties and the application of management’s judgment. If factors change and different assumptions are used, the share-based compensation expense could be materially different in the future. These assumptions are estimated as follows: Risk-free Interest Rate The risk-free interest rate assumption is based on the zero Expected Volatility The Company has limited historical data of its own to utilize in determining expected volatility. As such the Company based the volatility assumption on a combined weighted average of the Company’s own historical data and that of a selected peer group. The peer group was developed based on companies in the biotechnology and medical device industries whose shares are publicly traded. Expected Term The expected term represents the period of time that options are expected to be outstanding. As the Company does not (o) Income Taxes The Company accounts for income taxes based on the asset and liability method whereby deferred tax asset and liability account balances are determined based on differences between the financial reporting and tax bases of assets, liabilities, operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. A valuation allowance is provided when it is more likely than not not In evaluating the ability to recover its deferred income tax assets, the Company considers all available positive and negative evidence, including its operating results, forecasts of future taxable income, and ongoing tax planning. In the event the Company was to determine that it would be able to realize its deferred tax assets in the future in excess of their net recorded amount, it would make an adjustment to the valuation allowance, which would reduce the provision for income taxes. Conversely, in the event that all or part of the net deferred tax assets are determined not The Company recognizes and measures benefits for uncertain tax positions using a two first not not second 50% No (p) Fair Value of Financial Instruments The Company applies fair value accounting for all financial assets and liabilities and nonfinancial assets and liabilities that are required to be recognized or disclosed at fair value in the consolidated financial statements. The Company defines fair value as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Where observable prices or inputs are not The Company’s financial assets and liabilities consist principally of cash and cash equivalents, accounts receivable, and accounts payable. The fair value of the Company’s cash equivalents is determined based on quoted prices in active markets for identical assets. Cash in the Company’s operating bank accounts represents the difference between cash in the money market accounts and total cash and cash equivalents reported on the consolidated balance sheets. The recorded values of the Company’s accounts receivable and accounts payable approximate their current fair values due to the relatively short-term nature of these accounts. (q) Net Loss per Share Basic net loss per share is calculated by dividing the net loss by the weighted average number of shares of common stock outstanding and fully vested restricted stock units. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common share equivalents outstanding for the period determined using the treasury-stock method. Common stock equivalents are comprised of unvested restricted stock units, warrants to purchase common stock and options outstanding under the stock option plans. For all periods presented, there is no (r) Recent Accounting Pronouncements Recent accounting pronouncements issued by the Financial Accounting Standards Board, including its Emerging Issues Task Force, and the American Institute of Certified Public Accountants did not 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 Fair Value Measurements The fair value of financial instruments reflects the amounts that the Company estimates to receive in connection with the sale of an asset or paid in connection with the transfer of a liability in an orderly transaction between market participants at the measurement date (exit price). The Company follows a fair value hierarchy that prioritizes the use of inputs used in valuation techniques into the following three Level 1 Level 2 not Level 3 no The following table sets forth the fair value of the financial assets measured on a recurring basis and indicates the fair value hierarchy utilized to determine such fair value (in thousands). As of December 31, 2021 Level 1 Level 2 Level 3 Total Assets: Money market funds $ 12,917 $ — $ — $ 12,917 Cash in checking account — — — (45 ) Total cash and cash equivalent $ 12,917 $ — $ — $ 12,872 As of December 31, 2020 Level 1 Level 2 Level 3 Total Assets: Money market funds $ 20,662 $ — $ — $ 20,662 Cash in checking account — — — 745 Total cash and cash equivalent $ 20,662 $ — $ — $ 21,407

Note 4 - Property and Equipment

Note 4 - Property and Equipment, Net	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Property, Plant and Equipment Disclosure [Text Block]	( 4 Property and Equipment, Net Property and equipment, net consisted of the following (in thousands): December 31, December 31, 2021 2020 Computer equipment and software $ 133 $ 159 Laboratory and manufacturing equipment 460 550 Furniture and fixtures 26 59 Leasehold improvements 26 332 Construction in progress 74 70 Property and equipment, gross 719 1,170 Less accumulated depreciation (537 ) (1,025 ) Property and equipment, net $ 182 $ 145 Depreciation expense totaled approximately $60,000 and $68,000 for the years ended December 31, 2021 2020,

Note 5 - Operating Lease Right-

Note 5 - Operating Lease Right-of-use Asset, Net	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Lessee, Operating Leases [Text Block]	( 5 Operating Lease Right-of-Use Assets, Net The Company determines if an arrangement is a lease at inception by assessing whether it conveys the right to control the use of an identified asset for a period of time in exchange for consideration. The Company’s operating lease related to a property lease for its laboratory and corporate offices expired in December 2021, January 2027, 36 not ROU assets and lease liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. The Company’s lease does not not no The components of lease expense for the year ended December 31, 2021 2020, December 31, December 31, 2021 2020 Straight-line rent expense recognized for operating lease $ 623 $ 601 Variable rent expense recognized for operating lease 322 395 Total rent expense $ 945 $ 996 Weighted average remaining lease term (in years) 5.1 1.0 Weighted average discount rate 10.74 % 12.05 % Supplemental cash flow information related to the operating lease was as follows (in thousands): December 31, December 31, 2021 2020 Cash paid for amounts included in the measurement of lease liabilities $ 686 $ 630 Cash lease expense (imputed interest expense component of net income) 43 103 Total rent expense $ 729 $ 733 Future minimum lease payments under the operating lease as of December 31, 2021 For the years ending December 31, 2022 $ 424 2023 471 2024 485 2025 499 2026 514 Thereafter 43 Total undiscounted lease payments 2,436 Less imputed interest 568 Total operating lease liabilities $ 1,868

Note 6 - Collaborative Agreemen

Note 6 - Collaborative Agreements	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Collaborative Arrangement Disclosure [Text Block]	( 6 Collaborative Agreements The Company has entered into various collaborations related to clinical development. These agreements allow partners to utilize the Company’s enabling biotherapeutic delivery systems, including training and support during clinical and preclinical delivery of biotherapeutics. Under the terms of these agreements, the Company typically receives a use fee and payments for the systems and services provided. The Company gains access to certain data generated by its partners for use in its own product development efforts and also receives nonexclusive patent rights to any partner discovered BioCardia technology improvement inventions. Revenue from collaborative agreements is recognized in the Consolidated Statements of Operations in the line “Collaboration agreement revenue.”

Note 7 - Accrued Expenses and O

Note 7 - Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Accrued Liabilities and Other Current Liabilities Disclosure [Text Block]	( 7 Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following (in thousands): December 31, December 31, 2021 2020 Accrued expenses $ 240 $ 87 Accrued salaries and employee benefits 861 961 Accrued clinical trial costs 334 452 Grant liability 590 615 Customer deposits 96 90 Total $ 2,121 $ 2,205

Note 8 - Note Payable Under Pay

Note 8 - Note Payable Under Paycheck Protection Program	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Debt Disclosure [Text Block]	( 8 Note payable under Paycheck Protection Program On May 1, 2020, May 1, 2020. In accordance with the requirements of the CARES Act, the Borrower used the proceeds from the Note in accordance with the requirements of the PPP to cover certain qualified expenses, including payroll costs, rent and utility costs. Interest accrued on the Note at the rate of 1.00% On October 7, 2020, November 2, 2020. December 31, 2020.

Note 9 - Stockholders' Equity

Note 9 - Stockholders' Equity	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Stockholders' Equity Note Disclosure [Text Block]	( 9 Stockholders Equity $10.5 December 15, 2020, December 15 December 15 December 15 December 15 December 18, 2020, December 15 not December 15 3, October 9, 2020, October 20, 2020, December 15, 2020. $8.5 December 14, 2020, December 14 December 14 December 14 December 14 not December 16, 2020, December 14 not December 14 3, October 9, 2020, October 20, 2020, December 14, 2020. 2020 1 May 2020, 1 1 June 17, 2020, 1, 45 June 18, 2020. June 19, 2020. On June 8, 2020, two Lincoln Park Capital stock purchase agreement - March 29, 2021, $20 Pursuant to the Purchase Agreement, Lincoln Park purchased 373,832 shares of common stock, at a price of $5.35 per share, for a total gross purchase price of $2 million (the Initial Purchase) and the Company issued 80,000 shares of common stock as commitment shares, which included 5,000 commitment shares issued on a pro rata basis for the initial $2 36 not $2 may may may not may The Company controls the timing and amount of any sales of its common stock to Lincoln Park. There is no no may $4.2736 may not 9.99% The Purchase Agreement does not 36 may not may no As of December 31, 2021, not Warrants Number of Weighted Common Stock Average Warrants Exercise Price Balance, December 31, 2020 2,424,724 $ 6.36 Warrants for common stock sold — — Warrants for common stock exercised — — Balance, December 31, 2021 2,424,724 $ 6.36

Note 10 - Share-based Compensat

Note 10 - Share-based Compensation	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Share-based Payment Arrangement [Text Block]	( 10 Share-Based Compensation BioCardia Lifesciences adopted, and the BioCardia Lifesciences shareholders approved, the 2002 2002 “2002 2002 not not 2002 2016, 2016 “2016 2016 2016 2002 2016 four ten no 2016 2016 2016 first January 1, 2021). December 31, 2021, 2016 The Company recognizes in the consolidated statements of operations the grant-date fair value of stock options and other equity-based compensation. Share-based compensation expense for the years ended December 31, 2021 2020 Years ended December 31, 2021 2020 Research and development $ 795 $ 1,369 Selling, general and administrative 866 1,583 Total share-based compensation $ 1,661 $ 2,952 On January 29, 2020 ( No The repricing on January 29, 2020 three The following table summarizes activity under the Company’s stock option plans, including the 2002 2016 Options outstanding Number of shares Weighted average exercise price Weighted average remaining contractual term (years) Aggregate intrinsic value (in thousands) Balance, December 31, 2020 1,114,306 $ 5.89 7.5 $ 177.1 Stock options granted 772,435 3.56 Stock options exercised (1,580 ) 2.49 Stock options forfeited (235,350 ) 4.49 Stock options expired (125 ) 5.32 Balance, December 31, 2021 1,649,686 $ 5.00 7.6 $ — Exercisable, December 31, 2021 762,867 $ 6.62 6.0 $ — Options vested and expected to vest 1,649,686 $ 5.00 7.6 $ — The aggregate intrinsic value represents the difference between the total pre-tax value (i.e., the difference between the Company’s stock price and the exercise price) of stock options outstanding as of December 31, 2021, The total intrinsic value of options exercised was $3,000 and zero December 31, 2021 2020, December 31, 2021 2020 Employee, Director and Non-employee Share-Based Compensation During the years ended December 31, 2021 2020, Years ended December 31, 2021 2020 Risk-free interest rate 0.6 - 1.6% 0.4 - 1.6% Volatility 110 - 120% 107 - 112% Dividend yield None None Expected term (in years) 6.25 - 10.0 6.25 - 10.0 Unrecognized share-based compensation for employees, non-employee directors and non-employee options granted through December 31, 2021 Share-Based Compensation (RSUs) During the years ended December 31, 2021 2020, During the year ended December 31, 2020, April 2018 March 30, 2020. December 31, 2020, April 1, 2020 December 31, 2020. one two 2016 The following table summarizes the activity for RSUs during the years ended December 31, 2021 2020: Weighted average grant date Number of fair value shares per share Balance, December 31, 2020 224,311 $ 4.12 RSUs granted 131,375 3.61 RSUs released (118,472 ) 3.73 RSUs forfeited (36,943 ) 3.49 Balance, December 31, 2021 200,271 $ 4.13 RSUs vested and settled are converted into the Company’s common stock on a one one December 31, 2021, not not December 31, 2021

Note 11 - Concentrations

Note 11 - Concentrations	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Concentration Risk Disclosure [Text Block]	( 11 Concentrations Three customers accounted for approximately 67%, 13% and 13% of total revenues in 2021. 2020. December 31, 2021. December 31, 2020.

Note 12 - Net Loss Per Share

Note 12 - Net Loss Per Share	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Earnings Per Share [Text Block]	( 12 Net Loss per Share The following table sets forth the computation of the basic and diluted net loss per share for the years ended December 31, 2021 2020 Years ended December 31, 2021 2020 Net loss $ (12,623 ) $ (15,004 ) Weighted average shares used to compute net loss per share, basic and diluted 16,917,664 10,118,682 Net loss per share, basic and diluted $ (0.75 ) $ (1.48 ) The following weighted-average outstanding common stock equivalents were excluded from the computation of diluted net loss per share for the periods presented because including them would have been antidilutive: December 31, 2021 2020 Stock options to purchase common stock 1,649,686 1,114,306 Unvested restricted stock units 5,468 8,200 Common stock warrants 2,424,724 2,424,724 Total 4,079,878 3,547,230

Note 13 - Income Taxes

Note 13 - Income Taxes	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Income Tax Disclosure [Text Block]	( 13 Income Taxes The Company’s provision for income taxes for the years ended December 31, 2021 2020 The provision for income taxes differs from the amount which would result by applying the federal statutory income tax rate to pre-tax loss for the years ended December 31, 2021 2020. Years ended December 31, 2021 2020 Tax at federal statutory rate $ (2,651 ) $ (3,151 ) State, net of federal benefit — (449 ) Research and development credit (279 ) (276 ) Share-based compensation 264 649 PPP Note forgiveness — (107 ) Other 2 2 Change in valuation allowance 2,664 3,332 Total provision for income taxes $ — $ — Deferred income taxes reflect the net tax effects of temporary differences between carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes as well as net operating loss and tax credit carryforwards, net of any adjustment for unrecognized tax benefits. The components of the net deferred income tax assets as of December 31, 2021 2020 Years ended December 31, 2021 2020 Accrued compensation $ 191 $ 225 Inventory adjustments 15 335 Depreciation and amortization 24 90 Share-based compensation 595 686 Net operating loss and tax credit carryforwards 30,277 26,931 Other 2 173 Gross Deferred Tax Asset 31,104 28,440 Valuation Allowance (31,104 ) (28,440 ) Net deferred tax asset $ — $ — The Company had approximately $106.1 million and $62.4 million of federal and state net operating loss (NOL) carryforwards, respectively, as of December 31, 2021. 2022 2028 2021, 2020, 2019, 2018 no may may may one not 50% three Generally, utilization of the net operating loss carryforwards and credits may 382, 383, 1986, may not 382 383 As of December 31, 2021, 2028. no The Company does not not not December 31, 2021 2020. December 31, 2021 December 31, 2020 No The aggregate changes in the balance of gross unrecognized tax benefits were as follows (in thousands): Years ended December 31, 2021 2020 Balance, beginning of year $ 1,235 $ 1,046 Additions based on tax positions related to the current year 158 189 Reductions for tax positions related to prior years (25 ) — Balance, end of year $ 1,368 $ 1,235 Recognition of approximately $991,000 and $895,000 of unrecognized tax benefits would impact the effective rate at December 31, 2021 2020 2021

Note 14 - Contingencies and Con

Note 14 - Contingencies and Contingencies	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Contingencies Disclosure [Text Block]	( 14 Contingencies and Contingencies Contingencies may not

Note 15 - Grant Funding

Note 15 - Grant Funding	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Grant Funding [Text Block]	( 15 Grant Funding In June 2016, 1998 not three December 31, 2022. As of December 31, 2021, December 31, 2021. December 31, 2021.

Note 16 - Related Party Transac

Note 16 - Related Party Transactions	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Related Party Transactions Disclosure [Text Block]	( 16 Related Party Transactions Litigation Funding Agreement On April 9, 2020, No. 3:19 05645 Under the terms of the Funding Agreement, the Funder agreed to fund the legal fees and costs incurred by the Company in connection with the Litigation on and after March 1, 2020 (a) 50% of the remaining Litigation Proceeds, up to three (b) 30% of the remaining Litigation Proceeds. Although the Company is required under the terms of the Funding Agreement to consult with the Funder regarding any settlement in connection with the Litigation and to allow Funder to participate in any real-time settlement negotiations, the Company has the sole and exclusive right to settle on whatever terms it deems acceptable. On April 12, 2021, not In March 2022, December 31, 2021. December 31, 2021.

Note 17 - Employee Benefit Plan

Note 17 - Employee Benefit Plans	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Retirement Benefits [Text Block]	( 17 Employee Benefit Plans The Company’s U.S. employees are eligible to participate in a retirement and savings plan that qualifies under Section 401 may not December 31, 2021 2020,

Note 18 - Subsequent Events

Note 18 - Subsequent Events	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Subsequent Events [Text Block]	( 18 Subsequent Events In March 2022 16 March 17, 2022.

Significant Accounting Policies

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	(a) Basis of Presentation and Consolidation These consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (U.S. GAAP) and include all adjustments necessary for the fair presentation of the Company’s financial position for the periods presented. The consolidated financial statements include the accounts of the Company and its wholly owned subsidiary, BioCardia Lifesciences, Inc. All material intercompany accounts and transactions have been eliminated during the consolidation process.
Going Concern and Liquidity [Policy Text Block]	(b) Liquidity Going Concern The Company has incurred net losses and negative cash flows from operations since our inception and had an accumulated deficit of $128.7 million as of December 31, 2021. December 31, 2021 not fourth 2022. one not The Company’s ability to continue as a going concern and to continue further development of its therapeutic candidates beyond the fourth 2022, not not may may
Use of Estimates, Policy [Policy Text Block]	(c) Use of Estimates The preparation of the financial statements in accordance with U.S. GAAP requires management to make certain estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ materially from those estimates. Significant items subject to such estimates and assumptions include share-based compensation, the useful lives of property and equipment, right-of-use assets and related liabilities, incremental borrowing rate, allowances for doubtful accounts and sales returns, clinical accruals and assumptions used for revenue recognition.
Cash and Cash Equivalents, Policy [Policy Text Block]	(d) Cash Equivalents The Company classifies all highly liquid investments with an original maturity date of 90
Concentration Risk, Credit Risk, Policy [Policy Text Block]	(e) Concentration of Credit Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents. The Company maintains its cash at reputable U.S. financial institutions, which at times, exceed federally insured limits of $250,000 December 31, 2021, one not not
Accounts Receivable [Policy Text Block]	(f) Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable are recorded at the invoiced amount and do not not December 31, 2021 2020,
Property, Plant and Equipment, Policy [Policy Text Block]	(g) Property and Equipment, Net Property and equipment, net, are carried at cost less accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the related assets, as described in the table below. Maintenance and repairs are expensed as incurred. When assets are retired or otherwise disposed of, the cost and the related accumulated depreciation and amortization are removed from the accounts and any resulting gain or loss is reflected in the accompanying consolidated statements of operations. Asset Estimated useful lives (in years) Computer equipment and software 3 Laboratory and manufacturing equipment 3 Furniture and fixtures 3 Leasehold improvements 5 years or lease term, if shorter
Lessee, Leases [Policy Text Block]	(h) Right-of-Use Assets Operating lease right-of-use asset and liabilities 12 The Company’s lease liabilities are recognized at the applicable lease commencement date based on the present value of the lease payments required to be paid over the lease term. Variable lease payments are expensed as incurred and are not The Company's ROU assets are also recognized at the applicable lease commencement date. The ROU asset equals the carrying amount of the related lease liability, adjusted for any lease payments made prior to lease commencement and lease incentives provided by the lessor, if any. The Company reduces a ROU asset, and the periodic reduction is the difference between the straight-line total lease cost for the period (including reduction of initial direct costs) and the periodic accretion of the lease liability using the effective interest method. The Company’s lease terms may The Company’s lease contracts often include lease and non-lease components. The Company has elected the practical expedient offered by the standard to not The Company has elected not twelve
Property, Plant and Equipment, Impairment [Policy Text Block]	(i) Long-lived Assets Impairment assessment of long-lived assets may not December 31, 2021,
Clinical Trial Accruals, Policy [Policy Text Block]	(j) Clinical Trial Accruals As part of the process of preparing its consolidated financial statements, the Company is required to estimate its expenses resulting from its obligations under contracts with vendors and consultants and clinical site agreements in connection with conducting clinical trials. The financial terms of these contracts are subject to negotiation and may not not may may
Revenue [Policy Text Block]	(k) Revenue Recognition Net product revenue Collaboration agreement revenue In determining the appropriate amount of revenue to be recognized as it fulfills its obligations under each of its agreements, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations, including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. As part of the accounting for these arrangements, the Company must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. The Company uses key assumptions to determine the stand-alone selling price, which may not The Company applies judgment in determining whether a combined performance obligation is satisfied at a point in time or over time, and, if over time, concluding upon the appropriate method of measuring progress to be applied for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, as estimates related to the measure of progress change, related revenue recognition is adjusted accordingly. Changes in the Company’s estimated measure of progress are accounted for prospectively as a change in accounting estimate. The Company recognizes collaboration revenue by measuring the progress toward complete satisfaction of the performance obligation using an input measure. The Company will re-evaluate the estimate of expected costs to satisfy the performance obligation each reporting period and make adjustments for any significant changes. Amounts received prior to satisfying the revenue recognition criteria are recorded as deferred revenue in the Company’s consolidated balance sheets. If the related performance obligation is expected to be satisfied within the next twelve may not one December 31, 2021 2020, Multiple contracts with the same customer - two one one Contract costs - one not Contract modifications - one not not not
Standard Product Warranty, Policy [Policy Text Block]	(l) Product Warranties The Company provides a standard warranty of serviceability on all its products for the duration of the product’s shelf life, which is two not December 31, 2021 2020.
Research and Development Expense, Policy [Policy Text Block]	(m) Research and Development The Company’s research and development costs are expensed as incurred. Research and development expense include the costs of basic research activities as well as other research, engineering, and technical effort required to develop new products or services or make significant improvement to an existing product or manufacturing process. Research and development costs also include pre-approval regulatory and clinical trial expenses and support costs for collaborative partnering programs wherein the Company provides biotherapeutic delivery systems and customer training and support for their use in clinical trials and studies. The Company’s research and development costs consist primarily of: • Salaries, benefits and other personnel-related expenses, including share-based compensation; • Fees paid for services provided by clinical research organizations, research institutions, consultants and other outside service providers; • Costs to acquire and manufacture materials used in research and development activities and clinical trials; • Laboratory consumables and supplies; • Facility-related expenses allocated to research and development activities; • Fees to collaborators to license technology; and • Depreciation expense for equipment used for research and development and clinical purposes.
Compensation Related Costs, Policy [Policy Text Block]	(n) Share-Based Compensation The Company measures and recognizes share-based compensation expense for equity awards to employees, directors and consultants based on fair value at the grant date. The Company uses the Black-Scholes-Merton (BSM) option pricing model to calculate fair value of its stock option grants. The compensation cost for restricted stock awards is based on the closing price of the Company’s common stock on the date of grant. Share-based compensation expense recognized in the consolidated statements of operations is based on the period the services are performed and recognized as compensation expense on a straight-line basis over the requisite service period. The Company accounts for forfeitures as they occur. Measurement of nonemployee awards - The measurement of equity-classified nonemployee awards is fixed at the grant date, and the Company may 505 50 The BSM option pricing model requires the input of subjective assumptions, including the risk-free interest rate, the expected volatility in the value of the Company’s common stock, and the expected term of the option. These estimates involve inherent uncertainties and the application of management’s judgment. If factors change and different assumptions are used, the share-based compensation expense could be materially different in the future. These assumptions are estimated as follows: Risk-free Interest Rate The risk-free interest rate assumption is based on the zero Expected Volatility The Company has limited historical data of its own to utilize in determining expected volatility. As such the Company based the volatility assumption on a combined weighted average of the Company’s own historical data and that of a selected peer group. The peer group was developed based on companies in the biotechnology and medical device industries whose shares are publicly traded. Expected Term The expected term represents the period of time that options are expected to be outstanding. As the Company does not
Income Tax, Policy [Policy Text Block]	(o) Income Taxes The Company accounts for income taxes based on the asset and liability method whereby deferred tax asset and liability account balances are determined based on differences between the financial reporting and tax bases of assets, liabilities, operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. A valuation allowance is provided when it is more likely than not not In evaluating the ability to recover its deferred income tax assets, the Company considers all available positive and negative evidence, including its operating results, forecasts of future taxable income, and ongoing tax planning. In the event the Company was to determine that it would be able to realize its deferred tax assets in the future in excess of their net recorded amount, it would make an adjustment to the valuation allowance, which would reduce the provision for income taxes. Conversely, in the event that all or part of the net deferred tax assets are determined not The Company recognizes and measures benefits for uncertain tax positions using a two first not not second 50% No
Fair Value of Financial Instruments, Policy [Policy Text Block]	(p) Fair Value of Financial Instruments The Company applies fair value accounting for all financial assets and liabilities and nonfinancial assets and liabilities that are required to be recognized or disclosed at fair value in the consolidated financial statements. The Company defines fair value as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Where observable prices or inputs are not The Company’s financial assets and liabilities consist principally of cash and cash equivalents, accounts receivable, and accounts payable. The fair value of the Company’s cash equivalents is determined based on quoted prices in active markets for identical assets. Cash in the Company’s operating bank accounts represents the difference between cash in the money market accounts and total cash and cash equivalents reported on the consolidated balance sheets. The recorded values of the Company’s accounts receivable and accounts payable approximate their current fair values due to the relatively short-term nature of these accounts.
Earnings Per Share, Policy [Policy Text Block]	(q) Net Loss per Share Basic net loss per share is calculated by dividing the net loss by the weighted average number of shares of common stock outstanding and fully vested restricted stock units. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common share equivalents outstanding for the period determined using the treasury-stock method. Common stock equivalents are comprised of unvested restricted stock units, warrants to purchase common stock and options outstanding under the stock option plans. For all periods presented, there is no
New Accounting Pronouncements, Policy [Policy Text Block]	(r) Recent Accounting Pronouncements Recent accounting pronouncements issued by the Financial Accounting Standards Board, including its Emerging Issues Task Force, and the American Institute of Certified Public Accountants did not not

Note 2 - Significant Accounti_2

Note 2 - Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Property, Plant and Equipment, Useful Life [Table Text Block]	Asset Estimated useful lives (in years) Computer equipment and software 3 Laboratory and manufacturing equipment 3 Furniture and fixtures 3 Leasehold improvements 5 years or lease term, if shorter

Note 3 - Fair Value Measureme_2

Note 3 - Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	As of December 31, 2021 Level 1 Level 2 Level 3 Total Assets: Money market funds $ 12,917 $ — $ — $ 12,917 Cash in checking account — — — (45 ) Total cash and cash equivalent $ 12,917 $ — $ — $ 12,872 As of December 31, 2020 Level 1 Level 2 Level 3 Total Assets: Money market funds $ 20,662 $ — $ — $ 20,662 Cash in checking account — — — 745 Total cash and cash equivalent $ 20,662 $ — $ — $ 21,407

Note 4 - Property and Equipme_2

Note 4 - Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Property, Plant and Equipment [Table Text Block]	December 31, December 31, 2021 2020 Computer equipment and software $ 133 $ 159 Laboratory and manufacturing equipment 460 550 Furniture and fixtures 26 59 Leasehold improvements 26 332 Construction in progress 74 70 Property and equipment, gross 719 1,170 Less accumulated depreciation (537 ) (1,025 ) Property and equipment, net $ 182 $ 145

Note 5 - Operating Lease Righ_2

Note 5 - Operating Lease Right-of-use Asset, Net (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Lease, Cost [Table Text Block]	December 31, December 31, 2021 2020 Straight-line rent expense recognized for operating lease $ 623 $ 601 Variable rent expense recognized for operating lease 322 395 Total rent expense $ 945 $ 996 Weighted average remaining lease term (in years) 5.1 1.0 Weighted average discount rate 10.74 % 12.05 %
Schedule of Operating Leases Cash Flow Information [Table Text Block]	December 31, December 31, 2021 2020 Cash paid for amounts included in the measurement of lease liabilities $ 686 $ 630 Cash lease expense (imputed interest expense component of net income) 43 103 Total rent expense $ 729 $ 733
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	For the years ending December 31, 2022 $ 424 2023 471 2024 485 2025 499 2026 514 Thereafter 43 Total undiscounted lease payments 2,436 Less imputed interest 568 Total operating lease liabilities $ 1,868

Note 7 - Accrued Expenses and_2

Note 7 - Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Schedule of Accrued Liabilities and Other Current Liabilities [Table Text Block]	December 31, December 31, 2021 2020 Accrued expenses $ 240 $ 87 Accrued salaries and employee benefits 861 961 Accrued clinical trial costs 334 452 Grant liability 590 615 Customer deposits 96 90 Total $ 2,121 $ 2,205

Note 9 - Stockholders' Equity (

Note 9 - Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]	Number of Weighted Common Stock Average Warrants Exercise Price Balance, December 31, 2020 2,424,724 $ 6.36 Warrants for common stock sold — — Warrants for common stock exercised — — Balance, December 31, 2021 2,424,724 $ 6.36

Note 10 - Share-based Compens_2

Note 10 - Share-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Schedule of Share-based Compensation, Expense [Table Text Block]	Years ended December 31, 2021 2020 Research and development $ 795 $ 1,369 Selling, general and administrative 866 1,583 Total share-based compensation $ 1,661 $ 2,952
Share-based Payment Arrangement, Option, Activity [Table Text Block]	Options outstanding Number of shares Weighted average exercise price Weighted average remaining contractual term (years) Aggregate intrinsic value (in thousands) Balance, December 31, 2020 1,114,306 $ 5.89 7.5 $ 177.1 Stock options granted 772,435 3.56 Stock options exercised (1,580 ) 2.49 Stock options forfeited (235,350 ) 4.49 Stock options expired (125 ) 5.32 Balance, December 31, 2021 1,649,686 $ 5.00 7.6 $ — Exercisable, December 31, 2021 762,867 $ 6.62 6.0 $ — Options vested and expected to vest 1,649,686 $ 5.00 7.6 $ —
Schedule of Nonvested Restricted Stock Units Activity [Table Text Block]	Weighted average grant date Number of fair value shares per share Balance, December 31, 2020 224,311 $ 4.12 RSUs granted 131,375 3.61 RSUs released (118,472 ) 3.73 RSUs forfeited (36,943 ) 3.49 Balance, December 31, 2021 200,271 $ 4.13
Share-based Payment Arrangement, Option [Member]
Notes Tables
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	Years ended December 31, 2021 2020 Risk-free interest rate 0.6 - 1.6% 0.4 - 1.6% Volatility 110 - 120% 107 - 112% Dividend yield None None Expected term (in years) 6.25 - 10.0 6.25 - 10.0

Note 12 - Net Loss Per Share (T

Note 12 - Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Years ended December 31, 2021 2020 Net loss $ (12,623 ) $ (15,004 ) Weighted average shares used to compute net loss per share, basic and diluted 16,917,664 10,118,682 Net loss per share, basic and diluted $ (0.75 ) $ (1.48 )
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	December 31, 2021 2020 Stock options to purchase common stock 1,649,686 1,114,306 Unvested restricted stock units 5,468 8,200 Common stock warrants 2,424,724 2,424,724 Total 4,079,878 3,547,230

Note 13 - Income Taxes (Tables)

Note 13 - Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Notes Tables
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	Years ended December 31, 2021 2020 Tax at federal statutory rate $ (2,651 ) $ (3,151 ) State, net of federal benefit — (449 ) Research and development credit (279 ) (276 ) Share-based compensation 264 649 PPP Note forgiveness — (107 ) Other 2 2 Change in valuation allowance 2,664 3,332 Total provision for income taxes $ — $ —
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	Years ended December 31, 2021 2020 Accrued compensation $ 191 $ 225 Inventory adjustments 15 335 Depreciation and amortization 24 90 Share-based compensation 595 686 Net operating loss and tax credit carryforwards 30,277 26,931 Other 2 173 Gross Deferred Tax Asset 31,104 28,440 Valuation Allowance (31,104 ) (28,440 ) Net deferred tax asset $ — $ —
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]	Years ended December 31, 2021 2020 Balance, beginning of year $ 1,235 $ 1,046 Additions based on tax positions related to the current year 158 189 Reductions for tax positions related to prior years (25 ) — Balance, end of year $ 1,368 $ 1,235

Note 2 - Significant Accounti_3

Note 2 - Significant Accounting Policies 1 (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Retained Earnings (Accumulated Deficit), Ending Balance	$ (128,697,000)	$ (116,074,000)
Cash and Cash Equivalents, at Carrying Value, Ending Balance	12,872,000	21,407,000
Accounts Receivable, Allowance for Credit Loss, Current	22,000	16,000
Impairment of Long-Lived Assets Held-for-use	$ 0
Standard Product Warranty, Term (Year)	2 years
Standard Product Warranty Accrual, Ending Balance	$ 0	$ 0

Note 2 - Significant Accounti_4

Note 2 - Significant Accounting Policies 2 (Details Textual) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Month)		12 years
Revenue, Remaining Performance Obligation, Amount		$ 683,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period (Month)	12 months
Revenue, Remaining Performance Obligation, Amount	$ 847,000

Note 2 - Significant Accounti_5

Note 2 - Significant Accounting Policies - Estimated Useful Lives of Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2021
Computer Equipment and Software [Member]
Estimated useful lives (Year)	3 years
Laboratory and Manufacturing Equipment [Member]
Estimated useful lives (Year)	3 years
Furniture and Fixtures [Member]
Estimated useful lives (Year)	3 years

Note 3 - Fair Value Measureme_3

Note 3 - Fair Value Measurement - Fair Value of Assets Measured on a Recurring Basis (Details) - Fair Value, Recurring [Member] - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Cash and Cash Equivalents, Fair Value	$ 12,872	$ 21,407
Cash and Cash Equivalents, Fair Value	(12,872)	(21,407)
Money Market Funds [Member]
Cash and Cash Equivalents, Fair Value	12,917,000	20,662,000
Cash and Cash Equivalents, Fair Value	(12,917,000)	(20,662,000)
Demand Deposits [Member]
Cash and Cash Equivalents, Fair Value	45,000	745,000
Cash and Cash Equivalents, Fair Value	(45,000)	(745,000)
Fair Value, Inputs, Level 1 [Member]
Cash and Cash Equivalents, Fair Value	12,917	20,662
Cash and Cash Equivalents, Fair Value	(12,917)	(20,662)
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Cash and Cash Equivalents, Fair Value	12,917,000	20,662,000
Cash and Cash Equivalents, Fair Value	(12,917,000)	(20,662,000)
Fair Value, Inputs, Level 1 [Member] | Demand Deposits [Member]
Cash and Cash Equivalents, Fair Value	0	0
Cash and Cash Equivalents, Fair Value	0	0
Fair Value, Inputs, Level 2 [Member]
Cash and Cash Equivalents, Fair Value	0	0
Cash and Cash Equivalents, Fair Value	0	0
Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]
Cash and Cash Equivalents, Fair Value	0	0
Cash and Cash Equivalents, Fair Value	0	0
Fair Value, Inputs, Level 2 [Member] | Demand Deposits [Member]
Cash and Cash Equivalents, Fair Value	0	0
Cash and Cash Equivalents, Fair Value	0	0
Fair Value, Inputs, Level 3 [Member]
Cash and Cash Equivalents, Fair Value	0	0
Cash and Cash Equivalents, Fair Value	0	0
Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]
Cash and Cash Equivalents, Fair Value	0	0
Cash and Cash Equivalents, Fair Value	0	0
Fair Value, Inputs, Level 3 [Member] | Demand Deposits [Member]
Cash and Cash Equivalents, Fair Value	0	0
Cash and Cash Equivalents, Fair Value	$ 0	$ 0

Note 4 - Property and Equipme_3

Note 4 - Property and Equipment, Net (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Depreciation, Total	$ 60,000	$ 68,000

Note 4 - Property and Equipme_4

Note 4 - Property and Equipment, Net - Summary of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property and equipment, gross	$ 719	$ 1,170
Less accumulated depreciation	(537)	(1,025)
Property and equipment, net	182	145
Computer Equipment and Software [Member]
Property and equipment, gross	133	159
Laboratory and Manufacturing Equipment [Member]
Property and equipment, gross	460	550
Furniture and Fixtures [Member]
Property and equipment, gross	26	59
Leasehold Improvements [Member]
Property and equipment, gross	26	332
Construction in Progress [Member]
Property and equipment, gross	$ 74	$ 70

Note 5 - Operating Lease Righ_3

Note 5 - Operating Lease Right-of-use Asset, Net - Impact of New Lease Standard (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Straight-line rent expense recognized for operating lease	$ 623	$ 601
Variable rent expense recognized for operating lease	322	395
Total rent expense	$ 945	$ 996
Weighted average remaining lease term (in years) (Year)	5 years 1 month 6 days	1 year
Weighted average discount rate	10.74%	12.05%

Note 5 - Operating Lease Righ_4

Note 5 - Operating Lease Right-of-use Asset, Net - Supplement Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash paid for amounts included in the measurement of lease liabilities	$ 686	$ 630
Cash lease expense (imputed interest expense component of net income)	(43)	(103)
Total rent expense	$ 729	$ 733

Note 5 - Operating Lease Righ_5

Note 5 - Operating Lease Right-of-use Asset, Net - Future Minimum Lease Payments Under Operating Lease (Details) $ in Thousands	Dec. 31, 2021USD ($)
2022	$ 424
2023	471
2024	485
2025	499
2026	514
Thereafter	43
Total undiscounted lease payments	2,436
Less imputed interest	568
Total operating lease liabilities	$ 1,868

Note 7 - Accrued Expenses and_3

Note 7 - Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accrued expenses	$ 240	$ 87
Accrued salaries and employee benefits	861	961
Accrued clinical trial costs	334	452
Grant liability	590	615
Customer deposits	96	90
Total	$ 2,121	$ 2,205

Note 8 - Note Payable Under P_2

Note 8 - Note Payable Under Paycheck Protection Program (Details Textual) - USD ($)	Nov. 02, 2020	May 01, 2020	Dec. 31, 2021	Dec. 31, 2020
Gain (Loss) on Extinguishment of Debt, Total			$ 0	$ 509,000
Paycheck Protection Program CARES Act [Member]
Proceeds from Issuance of Long-term Debt, Total		$ 506,413
Debt Instrument, Principle Amount Forgiven	$ 506,000
Debt Instrument, Interest Amount Forgiven	$ 3,000
Gain (Loss) on Extinguishment of Debt, Total				$ 509,000

Note 9 - Stockholders' Equity_2

Note 9 - Stockholders' Equity (Details Textual) - USD ($)	Mar. 29, 2021	Dec. 18, 2020	Dec. 16, 2020	Jun. 19, 2020	Jun. 17, 2020	Jun. 08, 2020	Sep. 04, 2019	Dec. 31, 2021	Dec. 31, 2020	Aug. 06, 2019
Common Stock, Par or Stated Value Per Share (in dollars per share)								$ 0.001	$ 0.001
Stock Issued During Period, Value, New Issues								$ 1,942,000
Proceeds from Issuance of Common Stock								2,001,000	$ 0
Stock Issued During Period, Value, Issued for Services									148,000
Two Former Board Members [Member]
Stock Issued During Period, Shares, Issued for Services (in shares)						29,625
Stock Issued During Period, Value, Issued for Services						$ 148,000
Underwriters [Member]
Stock Issued During Period, Shares, New Issues (in shares)							75,000
The $10.5 Million Registered Direct Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares)		2,038,836
Common Stock, Par or Stated Value Per Share (in dollars per share)		$ 0.001
Shares Issued, Price Per Share (in dollars per share)		$ 5.15
Stock Issued During Period, Value, New Issues		$ 10,500,000							9,765,000
Placement Agent Fee		7.00%
Proceeds from Issuance of Common Stock		$ 9,800,000						0	10,500,000
The $8.5 Million Registered Direct Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares)			1,789,474
Common Stock, Par or Stated Value Per Share (in dollars per share)			$ 0.001
Shares Issued, Price Per Share (in dollars per share)			$ 4.75
Stock Issued During Period, Value, New Issues			$ 8,500,000						7,827,000
Placement Agent Fee			7.00%
Proceeds from Issuance of Common Stock			$ 7,800,000					0	8,500,000
Placement Agent Maximum Expenses Reimbursement Amount			$ 40,000
Public Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares)				4,762,000
Common Stock, Par or Stated Value Per Share (in dollars per share)				$ 0.001
Shares Issued, Price Per Share (in dollars per share)				$ 2.10
Stock Issued During Period, Value, New Issues									10,273,000
Proceeds from Issuance of Common Stock				$ 10,300,000				$ 0	$ 11,500,000
Underwriters, Additional Common Shares Authorized to Purchase (in shares)					714,190
Purchase Agreement with Lincoln Park [Member]
Stock Issued During Period, Shares, New Issues (in shares)	373,832							0
Shares Issued, Price Per Share (in dollars per share)	$ 5.35
Proceeds from Issuance of Common Stock	$ 2,000,000
Sale of Stock, Aggregate Value, Maximum	$ 20,000,000
Stock Issuable, Commitment Shares on Pro Rata Basis (in shares)	50,000
Stock Issued During the Period, Shares, Commission Fees (in shares)	80,000
Stock Issued During the Period, Commitment Shares Issued on Pro Rata Basis (in shares)	5,000
Conditional Issuance, Maximum Number of Shares Allowed to be Purchased (in shares)	100,000
Stock Purchase Agreement Accelerated Purchase, Maximum, Percent of Shares Purchased on the Same Trading Day	300.00%
Stock Purchase Agreement Accelerated Purchase, Maximum, Percent of Total Common Shares Traded During Specified Period	30.00%
Maximum Number of Shares Allowed to be Issued Including Commitment Shares (in shares)	3,266,177
Percentage of Common Stock Outstanding	19.99%
Private Placement Unit [Member]
Number of Common Stock in Each Unit (in shares)										1

Note 9 - Stockholders' Equity -

Note 9 - Stockholders' Equity - Warrants (Details)	12 Months Ended
	Dec. 31, 2021$ / sharesshares
Balance, beginning (in shares) | shares	2,424,724
Balance, beginning, weighted average exercise price (in dollars per share) | $ / shares	$ 6.36
Warrants for common stock sold (in shares) | shares	0
Warrants for common stock sold, weighted average exercise price (in dollars per share) | $ / shares	$ 0
Warrants for common stock exercised (in shares) | shares	0
Warrants for common stock exercised, weighted average exercise price (in dollars per share) | $ / shares	$ 0
Balance, ending (in shares) | shares	2,424,724
Balance, ending, weighted average exercise price (in dollars per share) | $ / shares	$ 6.36

Note 10 - Share-based Compens_3

Note 10 - Share-based Compensation (Details Textual) - USD ($)	Jan. 01, 2021	Jan. 29, 2020	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)		$ 5.32	$ 3.56
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)		515,036	772,435
Share-based Payment Arrangement, Expensed and Capitalized, Amount, Total		$ 569,000
Share-based Payment Arrangement, Expense		412,000	$ 1,661,000	$ 2,952,000
Share-based Payment Arrangement, Amount Capitalized		$ 157,000
Share-based Compensation Arrangement by Share-based Payment Award, Remaining Weighted Average Award Vesting Period (Year)		3 years
Share Price (in dollars per share)			$ 1.94
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value			$ 3,000	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)			$ 3.10	$ 1.73
Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)			772,435	342,232
Non-employee Directors and Employees [Member]
Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount			$ 2,500,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)			2 years 9 months 18 days
Minimum [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)		$ 10.05
Maximum [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)		$ 97.21
The 2016 Plan [Member]
Annual Increase, Percentage of Common Shares Outstanding			4.00%
Annual Increase, Number of Common Shares (in shares)	1,000,000		268,997
Share-based Payment Arrangement, Option [Member]
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 Payment Arrangement, Option [Member] | The 2016 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)			133,330
Restricted Stock Units (RSUs) [Member]
Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount			$ 61,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)			4 months 24 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)			131,375
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)			118,472
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Ending Balance (in shares)			200,271	224,311
Restricted Stock Units (RSUs) [Member] | Non-employee Directors and Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number, Ending Balance (in shares)			200,271
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)			194,803
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Ending Balance (in shares)			5,468
Restricted Stock Units (RSUs) [Member] | Management [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)			112,583	113,976
Restricted Stock Units (RSUs) [Member] | Director [Member]
Number of Share-based Awards Granted Quarterly, Numerator in Ratio				$ 92,500
Number of Share-based Awards Granted Quarterly, Denominator in Ratio				4
Restricted Stock Units (RSUs) [Member] | Director [Member] | Share-based Payment Arrangement, Tranche One [Member]
Share-based Payment Arrangement, Expense				$ 190,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)				122,977
Restricted Stock Units (RSUs) [Member] | Director [Member] | Share-based Payment Arrangement, Tranche Two [Member]
Share-based Payment Arrangement, Expense				$ 613,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)				69,321
Restricted Stock Units (RSUs) [Member] | Maximum [Member] | Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)				2 years

Note 10 - Share-based Compens_4

Note 10 - Share-based Compensation - Share-based Compensation Expense (Details) - USD ($)	Jan. 29, 2020	Dec. 31, 2021	Dec. 31, 2020
Share-based compensation expense	$ 412,000	$ 1,661,000	$ 2,952,000
Research and Development Expense [Member]
Share-based compensation expense		795,000	1,369,000
Selling, General and Administrative Expenses [Member]
Share-based compensation expense		$ 866,000	$ 1,583,000

Note 10 - Share-based Compens_5

Note 10 - Share-based Compensation - Stock Option Activity (Details) - USD ($)	Jan. 29, 2020	Dec. 31, 2021	Dec. 31, 2020
Stock options outstanding, beginning of period (in shares)		1,114,306
Balance, weighted average exercise price, beginning of period (in dollars per share)		$ 5.89
Stock options outstanding, weighted average remaining contractual term (Year)		7 years 7 months 6 days	7 years 6 months
Stock options outstanding, aggregate intrinsic value			$ 177,100
Stock options granted (in shares)	515,036	772,435
Stock options granted, weighted average exercise price (in dollars per share)	$ 5.32	$ 3.56
Stock options exercised (in shares)		(1,580)
Stock options exercised, weighted average exercise price (in dollars per share)		$ 2.49
Stock options forfeited (in shares)		(235,350)
Stock options forfeited, weighted average exercise price (in dollars per share)		$ 4.49
Stock options expired (in shares)		(125)
Stock options expired, weighted average exercise price (in dollars per share)		$ 5.32
Stock options outstanding, end of period (in shares)		1,649,686	1,114,306
Balance, weighted average exercise price, end of period (in dollars per share)		$ 5	$ 5.89
Exercisable, December 31, 2021 (in shares)		762,867
Options exercisable, weighted average exercise price (in dollars per share)		$ 6.62
Options exercisable, weighted average remaining contractual term (Year)		6 years
Options vested and expected to vest (in shares)		1,649,686
Options vested and expected to vest, weighted average exercise price (in dollars per share)		$ 5
Options vested and expected to vest, weighted average remaining contractual term (Year)		7 years 7 months 6 days

Note 10 - Share-based Compens_6

Note 10 - Share-based Compensation - Valuation Assumptions for Employee Stock Options (Details) - Share-based Payment Arrangement, Option [Member]	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Minimum [Member]
Risk-free interest rate	0.60%	0.40%
Volatility	110.00%	107.00%
Expected term (Year)	6 years 3 months	6 years 3 months
Maximum [Member]
Risk-free interest rate	1.60%	1.60%
Volatility	120.00%	112.00%
Expected term (Year)	10 years	10 years

Note 10 - Share-based Compens_7

Note 10 - Share-based Compensation - Summary of Non-vested RSUs (Details) - Restricted Stock Units (RSUs) [Member]	12 Months Ended
	Dec. 31, 2021$ / sharesshares
Balance, shares (in shares) | shares	224,311
Balance, weighted average grant date fair value per share (in dollars per share) | $ / shares	$ 4.12
RSUs granted, shares (in shares) | shares	131,375
RSUs granted, weighted average grant date fair value per share (in dollars per share) | $ / shares	$ 3.61
RSUs released, shares (in shares) | shares	(118,472)
RSUs released, weighted average grant date fair value per share (in dollars per share) | $ / shares	$ 3.73
RSUs forfeited, shares (in shares) | shares	(36,943)
RSUs forfeited, weighted average grant date fair value per share (in dollars per share) | $ / shares	$ 3.49
Balance, shares (in shares) | shares	200,271
Balance, weighted average grant date fair value per share (in dollars per share) | $ / shares	$ 4.13

Note 11 - Concentrations (Detai

Note 11 - Concentrations (Details Textual) - Customer Concentration Risk [Member]	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Revenue Benchmark [Member] | Customer One [Member]
Concentration Risk, Percentage	67.00%	70.00%
Revenue Benchmark [Member] | Customer Two [Member]
Concentration Risk, Percentage	13.00%	16.00%
Revenue Benchmark [Member] | Customer Three [Member]
Concentration Risk, Percentage	13.00%
Accounts Receivable [Member] | Customer One [Member]
Concentration Risk, Percentage	24.00%	22.00%
Accounts Receivable [Member] | Customer Two [Member]
Concentration Risk, Percentage	14.00%	18.00%
Accounts Receivable [Member] | Customer Three [Member]
Concentration Risk, Percentage	12.00%	11.00%
Accounts Receivable [Member] | Customer Four [Member]
Concentration Risk, Percentage	12.00%

Note 12 - Net Loss Per Share -

Note 12 - Net Loss Per Share - Basic and Diluted Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Net loss	$ (12,623)	$ (15,004)
Weighted-average shares used in computing net loss per share, basic and diluted (in shares)	16,917,664	10,118,682
Net loss per share, basic and diluted (in dollars per share)	$ (0.75)	$ (1.48)

Note 12 - Net Loss Per Share _2

Note 12 - Net Loss Per Share - Anti-dilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Antidilutive securities (in shares)	4,079,878	3,547,230
Share-based Payment Arrangement, Option [Member]
Antidilutive securities (in shares)	1,649,686	1,114,306
Restricted Stock Units (RSUs) [Member]
Antidilutive securities (in shares)	5,468	8,200
Warrant [Member]
Antidilutive securities (in shares)	2,424,724	2,424,724

Note 13 - Income Taxes (Details

Note 13 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Expense (Benefit), Total	$ 0	$ 0
Deferred Tax Liabilities, Net, Total	0	0
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	2,700,000	3,300,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	991,000	895,000
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total		$ 62,400,000
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards, Total	106,100,000
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	3,100,000
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	$ 2,300,000

Note 13 - Income Taxes - Effect

Note 13 - Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Tax at federal statutory rate	$ (2,651)	$ (3,151)
State, net of federal benefit	0	(449)
Research and development credit	(279)	(276)
Share-based compensation	264	649
PPP Note forgiveness	0	(107)
Other	2	2
Change in valuation allowance	2,664	3,332
Total provision for income taxes	$ 0	$ 0

Note 13 - Income Taxes - Compon

Note 13 - Income Taxes - Components of the Net Deferred Income Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accrued compensation	$ 191	$ 225
Inventory adjustments	15	335
Depreciation and amortization	24	90
Share-based compensation	595	686
Net operating loss and tax credit carryforwards	30,277	26,931
Other	2	173
Gross Deferred Tax Asset	31,104	28,440
Valuation Allowance	(31,104)	(28,440)
Net deferred tax asset	$ 0	$ 0

Note 13 - Income Taxes - Aggreg

Note 13 - Income Taxes - Aggregate Changes in the Balance of Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Balance, beginning of year	$ 1,235	$ 1,046
Additions based on tax positions related to the current year	158	189
Reductions for tax positions related to prior years	(25)	0
Balance, end of year	$ 1,368	$ 1,235

Note 15 - Grant Funding (Detail

Note 15 - Grant Funding (Details Textual) - Grant Agreement [Member] - TEDCO [Member] - USD ($)	1 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2021
Grant Funding Available	$ 750,000
Grant Funding, Term of Grant (Year)	3 years
Proceeds from Grant Funding		$ 750,000
Research and Development Expense Reduction from Qualified Grant Funding		160,000
Deferred Revenue from Grants, Current		$ 590,000

Note 16 - Related Party Trans_2

Note 16 - Related Party Transactions (Details Textual) - BSLF, L.L.C. [Member] - Funding Agreement [Member] - USD ($)	1 Months Ended	12 Months Ended
	Mar. 29, 2022	Dec. 31, 2021
Percentage of Remaining Litigation Proceeds Up to Three Times the Actual Funding Amount		50.00%
Percentage of Remaining Litigation Proceeds		30.00%
Increase (Decrease) in Accounts Payable, Related Parties		$ (523,000)
Due from Related Parties, Total		562,000
Selling, General and Administrative Expenses [Member]
Legal Fees		195,000
Accrued Expenses and Other Current Liabilities [Member]
Accounts Payable, Related Parties		$ 156,000
Subsequent Event [Member]
Legal Fees	$ 688,000
Maximum Discount on Legal Service	$ 300,000

Note 17 - Employee Benefit Pl_2

Note 17 - Employee Benefit Plans (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	75.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 30,000	$ 26,000

Note 18 - Subsequent Events (De

Note 18 - Subsequent Events (Details Textual)	Mar. 17, 2022USD ($)
BSLF, L.L.C. [Member] | Funding Agreement [Member] | Subsequent Event [Member]
Related Party Transaction, Amounts of Transaction	$ 156,000