BioCardia (BCDA) 10-Q 8 Nov 23 2023 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2023	Oct. 31, 2023
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2023
Document Transition Report	false
Entity File Number	001-38999
Entity Registrant Name	BioCardia, Inc
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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		21,619,432
Entity Central Index Key	0000925741
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3
Amendment Flag	false
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
Warrant [Member]
Document Information [Line Items]
Title of 12(b) Security	Warrant to Purchase Common Stock
Trading Symbol	BCDAW
Security Exchange Name	NASDAQ

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Cash and cash equivalents	$ 1,835	$ 7,363
Accounts receivable, net of allowance for doubtful accounts of $22 and $11 as of September 30, 2023 and December 31, 2022, respectively	104	201
Prepaid expenses and other current assets	177	300
Total current assets	2,116	7,864
Property and equipment, net	114	170
Operating lease right-of-use asset, net	1,346	1,588
Other assets	171	171
Total assets	3,747	9,793
Accounts payable	507	683
Accrued expenses and other current liabilities	2,502	2,246
Deferred revenue	0	341
Operating lease liability - current	321	315
Total current liabilities	3,330	3,585
Operating lease liability - noncurrent	1,077	1,316
Total liabilities	4,407	4,901
Commitments and Contingencies
Preferred stock, $0.001 par value, 25,000,000 shares authorized and no shares issued and outstanding as of September 30, 2023 and December 31, 2022	0	0
Common stock, $0.001 par value, 100,000,000 shares authorized, 21,619,432 and 20,076,773 shares issued and outstanding as of September 30, 2023 and December 31, 2022, respectively	22	20
Additional paid-in capital	149,421	145,476
Accumulated deficit	(150,103)	(140,604)
Total stockholders’ equity (deficit)	(660)	4,892
Total liabilities and stockholders’ equity (deficit)	$ 3,747	$ 9,793

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Sep. 30, 2023	Mar. 31, 2023	Dec. 31, 2022
Accounts Receivable, Allowance for Credit Loss, Current	$ 22		$ 11
Preferred Stock, Par or Stated Value Per Share (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 or Stated Value Per Share (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)	21,619,432		20,076,773
Common Stock, Shares, Outstanding (in shares)	21,619,432		20,076,773

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Total revenue	$ 357	$ 212	$ 464	$ 1,246
Research and development	1,872	2,144	6,570	6,634
Selling, general and administrative	1,083	1,128	3,454	3,495
Total costs and expenses	2,955	3,272	10,024	10,129
Operating loss	(2,598)	(3,060)	(9,560)	(8,883)
Total other income, net	24	3	61	4
Net loss	$ (2,574)	$ (3,057)	$ (9,499)	$ (8,879)
Net loss per share, basic and diluted (in dollars per share)	$ (0.12)	$ (0.17)	$ (0.46)	$ (0.51)
Weighted-average shares used in computing net loss per share, basic and diluted (in shares)	21,615,655	17,844,991	20,731,050	17,523,837
Product [Member]
Total revenue	$ 0	$ 2	$ 0	$ 3
Collaboration Agreement [Member]
Total revenue	$ 357	$ 210	$ 464	$ 1,243

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock [Member] Restricted Stock Units (RSUs) [Member] Management [Member]	Common Stock [Member] ATM [Member]	Common Stock [Member]	Additional Paid-in Capital [Member] Restricted Stock Units (RSUs) [Member] Management [Member]	Additional Paid-in Capital [Member] ATM [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member] Restricted Stock Units (RSUs) [Member] Management [Member]	Retained Earnings [Member] ATM [Member]	Retained Earnings [Member]	Restricted Stock Units (RSUs) [Member] Management [Member]	ATM [Member]	Total
Balance (in shares) at Dec. 31, 2021			16,871,265
Balance at Dec. 31, 2021			$ 17			$ 139,055			$ (128,697)			$ 10,375
Share-based compensation						319						319
Net loss									(3,325)			(3,325)
Share-based compensation						319						319
Balance (in shares) at Mar. 31, 2022			16,871,265
Balance at Mar. 31, 2022			$ 17			139,374			(132,022)			7,369
Balance (in shares) at Dec. 31, 2021			16,871,265
Balance at Dec. 31, 2021			$ 17			139,055			(128,697)			10,375
Net loss												(8,879)
Balance (in shares) at Sep. 30, 2022			17,841,927
Balance at Sep. 30, 2022			$ 18			141,655			(137,576)			4,097
Balance (in shares) at Mar. 31, 2022			16,871,265
Balance at Mar. 31, 2022			$ 17			139,374			(132,022)			7,369
Share-based compensation			0			304			0			304
Net loss			$ 0			0			(2,497)			(2,497)
Stock Issued During Period, Shares, Restricted Stock Award, Gross (in shares)			311,929
Restricted stock units issued to settle management bonus obligations	$ 0			$ 271			$ 0			$ 271
Sale of common stock, net of issuance costs (in shares)		575,000
Sale of common stock, net of issuance costs		$ 1			$ 1,286			$ 0			$ 1,287
Share-based compensation			$ 0			304			0			304
Restricted stock units vested and issued (in shares)			311,929
Balance (in shares) at Jun. 30, 2022			17,758,194
Balance at Jun. 30, 2022			$ 18			141,235			(134,519)			6,734
Balance (in shares) at Mar. 31, 2022			16,871,265
Balance at Mar. 31, 2022			$ 17			139,374			(132,022)			7,369
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs											232
Issuance costs from sale of common stock on June 21, 2023											(232)
Balance (in shares) at Sep. 30, 2022			17,841,927
Balance at Sep. 30, 2022			$ 18			141,655			(137,576)			4,097
Balance (in shares) at Jun. 30, 2022			17,758,194
Balance at Jun. 30, 2022			$ 18			141,235			(134,519)			6,734
Share-based compensation			0			280			0			280
Net loss			$ 0			0			(3,057)			(3,057)
Stock Issued During Period, Shares, Restricted Stock Award, Gross (in shares)			17,029
Sale of common stock, net of issuance costs (in shares)		66,704
Sale of common stock, net of issuance costs		$ 0			140			0			140
Share-based compensation			$ 0			280			0			280
Restricted stock units vested and issued			$ 0			0			0			0
Restricted stock units vested and issued (in shares)			17,029
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs											1
Issuance costs from sale of common stock on June 21, 2023											(1)
Balance (in shares) at Sep. 30, 2022			17,841,927
Balance at Sep. 30, 2022			$ 18			141,655			(137,576)			4,097
Balance (in shares) at Dec. 31, 2022			20,076,773
Balance at Dec. 31, 2022			$ 20			145,476			(140,604)			4,892
Share-based compensation			0			278			0			278
Net loss			$ 0			0			(3,501)			(3,501)
Stock Issued During Period, Shares, Restricted Stock Award, Gross (in shares)			18,792
Sale of common stock, net of issuance costs (in shares)		106,241
Sale of common stock, net of issuance costs		$ 0			231			0			231
Share-based compensation			$ 0			278			0			278
Exercise of common stock options (in shares)			199
Exercise of common stock options						0						0
Restricted stock units vested and issued (in shares)			18,792
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs											13
Issuance costs from sale of common stock on June 21, 2023											(13)
Balance (in shares) at Mar. 31, 2023			20,202,005
Balance at Mar. 31, 2023			$ 20			145,985			(144,105)			1,900
Balance (in shares) at Dec. 31, 2022			20,076,773
Balance at Dec. 31, 2022			$ 20			145,476			(140,604)			4,892
Net loss												$ (9,499)
Exercise of common stock options (in shares)												199
Balance (in shares) at Sep. 30, 2023			21,619,432
Balance at Sep. 30, 2023			$ 22			149,421			(150,103)			$ (660)
Balance (in shares) at Mar. 31, 2023			20,202,005
Balance at Mar. 31, 2023			$ 20			145,985			(144,105)			1,900
Share-based compensation						317						317
Net loss									(3,424)			(3,424)
Stock Issued During Period, Shares, Restricted Stock Award, Gross (in shares)			222,405
Restricted stock units issued to settle management bonus obligations	$ 0			$ 342			$ 0			$ 342
Sale of common stock, net of issuance costs (in shares)		28,599	1,133,141
Sale of common stock, net of issuance costs		$ 0	$ 1		29	2,469		0	0		29	2,470
Share-based compensation						317						317
Restricted stock units vested and issued			$ 1			0			0			1
Restricted stock units vested and issued (in shares)			222,405
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs											29	177
Issuance costs from sale of common stock on June 21, 2023											(29)	(177)
Balance (in shares) at Jun. 30, 2023			21,586,150
Balance at Jun. 30, 2023			$ 22			149,142			(147,529)			1,635
Share-based compensation			0			251			0			251
Net loss			0			0			(2,574)			(2,574)
Sale of common stock, net of issuance costs (in shares)		33,282
Sale of common stock, net of issuance costs		$ 0			$ 45			$ 0			45
Share-based compensation			0			251			0			251
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs			0			17			0		48	17
Issuance costs from sale of common stock on June 21, 2023			$ 0			(17)			0		$ (48)	(17)
Balance (in shares) at Sep. 30, 2023			21,619,432
Balance at Sep. 30, 2023			$ 22			$ 149,421			$ (150,103)			$ (660)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) (Parentheticals) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Sep. 30, 2022
ATM [Member]
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	$ 48	$ 29	$ 13	$ 1	$ 232
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	$ 17	$ 177

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Net loss	$ (9,499)	$ (8,879)
Depreciation	64	61
Reduction in the carrying amount of right-of-use assets	242	219
Share-based compensation	846	903
Loss on disposal of property and equipment	4	0
Accounts receivable	97	(153)
Prepaid expenses and other current assets	123	275
Accounts payable	(24)	380
Accrued expenses and other current liabilities	598	265
Deferred revenue	(341)	(469)
Operating lease liability	(233)	(166)
Net cash used in operating activities	(8,123)	(7,564)
Purchase of property and equipment	(12)	(68)
Net cash used in investing activities	(12)	(68)
Proceeds from sales of common stock	3,042	1,658
Issuance costs of sale of common stock	(435)	(231)
Net cash provided by financing activities	2,607	1,427
Net change in cash and cash equivalents	(5,528)	(6,205)
Cash and cash equivalents at beginning of period	7,363	12,872
Cash and cash equivalents at end of period	1,835	6,667
Unpaid issuance costs of common stock	20	0
Issuance of restricted stock units in lieu of cash bonus obligations	$ 564	$ 401

Note 1 - Summary of Business an

Note 1 - Summary of Business and Basis of Presentation	9 Months Ended
	Sep. 30, 2023
Notes to Financial Statements
Business Description and Basis of Presentation [Text Block]	(1) Summary of Business and Basis of Presentation (a) 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. We are advancing two cell therapy platforms derived from bone marrow in clinical trials today. Our CardiAMP® autologous mononuclear cell therapy platform is being advanced for two clinical indications: ischemic heart failure with reduced ejection fraction (HFrEF) and refractory angina resulting from chronic myocardial ischemia (CMI). Our neurokinin-1 receptor positive (NK1R+) allogeneic mesenchymal stem cell (MSC) therapy platform is being advanced as an “off the shelf” cell therapy for two clinical indications: the treatment of ischemic HFrEF and for acute respiratory distress syndrome (ARDS). Our autologous CardiAMP and our allogeneic NK1R+ cell therapies intended for cardiac indications of HFrEF and CMI are enabled by our Helix™ minimally invasive intramyocardial therapeutic delivery platform. We partner this therapeutic delivery platform selectively with others seeking to develop biotherapeutic interventions for local delivery to the heart. To date, we have devoted substantially all our resources to research and development efforts relating to our therapeutic candidates and biotherapeutic delivery systems including conducting clinical trials, developing manufacturing and sales capabilities, in-licensing related intellectual property, providing general and administrative support for these operations and protecting our intellectual property. We manage our operations as a single segment for the purposes of assessing performance and making operating decisions.

Note 2 - Significant Accounting

Note 2 - Significant Accounting Policies	9 Months Ended
	Sep. 30, 2023
Notes to Financial Statements
Significant Accounting Policies [Text Block]	(2) Significant Accounting Policies (a) Basis of Preparation The accompanying condensed consolidated balance sheets, statements of operations, stockholders’ equity (deficit), and cash flows as of September 30, 2023, and for the three and nine months ended September 30, 2023 and 2022 are unaudited. The condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (U.S. GAAP) and applicable rules and regulations of the Securities and Exchange Commission (SEC) for interim financial information and on a basis consistent with the annual financial statements and, in the opinion of management, reflect all adjustments which include only normal recurring adjustments, necessary to present fairly our financial position as of September 30, 2023, results of operations for the three and nine months ended September 30, 2023 and 2022, and cash flows for the nine months ended September 30, 2023 and 2022. The results for the three and nine months ended September 30, 2023 are not necessarily indicative of the results to be expected for the year ended December 31, 2023 or for any other interim period or for any other future year. These condensed consolidated financial statements should be read in conjunction with the audited financial statements and related notes included in our Annual Report on Form 10-K for the year ended December 31, 2022, filed with the SEC on March 29, 2023. (b) Liquidity Going Concern We have incurred net losses and negative cash flows from operations since our inception and had an accumulated deficit of approximately $150.1 million as of September 30, 2023. Management expects operating losses and negative cash flows to continue through at least the next several years. We expect to incur increasing costs as we advance our trials and development activities. Therefore, absent additional funding, management believes cash and cash equivalents of $1.8 million as of September 30, 2023 are not sufficient to fund our planned expenditures and meet our obligations beyond January 2024. These factors raise substantial doubt about our ability to continue as a going concern beyond one year from the date these financial statements are issued. The financial statements do not include any adjustments that might result from the outcome of this uncertainty. Our ability to continue as a going concern and to continue further development of our therapeutic candidates beyond January 2024 will require us to raise additional capital. We plan to raise additional capital, potentially including debt and equity arrangements, to finance our future operations. The Company has also taken steps to reduce operating expenses to extend the cash runway. While we believe the plan to raise additional funds will alleviate the conditions that raise substantial doubt, the plan is not entirely within our control and cannot be assessed as being probable of occurring. If adequate funds are not available, we may be required to further reduce operating expenses, delay or reduce the scope of our product development programs, obtain funds through arrangements with others that may require us to relinquish rights to certain of our technologies or products that we would otherwise seek to develop or commercialize, or cease operations. (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) Principles of Consolidation The condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary, BioCardia Lifesciences, Inc. All intercompany accounts and transactions have been eliminated during the consolidation process. (e) Concentration of Credit Risk Financial instruments that potentially subject us to a concentration of credit risk consist of cash and cash equivalents. Our cash at times exceeds federally insured limits of $250,000 per customer. On September 30, 2023, approximately 98% of our cash and cash equivalents were held by one financial institution and total amounts on deposit were approximately $1.6 million in excess of FDIC insurance limits. We have not recognized any losses from credit risks on such accounts since inception. (f) Changes to Significant Accounting Policies Our significant accounting policies are described in Note 2 of the notes to the consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2022, filed with the SEC on March 29, 2023. There have been no changes to those policies. (g) Recent Accounting Pronouncements Recent accounting pronouncements issued by the Financial Accounting Standards Board (FASB), including its Emerging Issues Task Force, did not or are not believed by management to have a material impact on our financial statement presentation or disclosures.

Note 3 - Fair Value Measurement

Note 3 - Fair Value Measurement	9 Months Ended
	Sep. 30, 2023
Notes to Financial Statements
Fair Value Disclosures [Text Block]	(3) Fair Value Measurement The fair value of financial instruments reflects the amounts that we estimate 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). We follow a fair value hierarchy that prioritizes the use of inputs used in valuation techniques into the following three levels: Level 1 – quoted prices in active markets for identical assets and liabilities. Level 2 – observable inputs other than quoted prices in active markets for identical assets and liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 – unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The following table sets forth the fair value of our financial assets measured on a recurring basis and indicates the fair value hierarchy utilized to determine such fair value (in thousands): As of September 30, 2023 Level 1 Level 2 Level 3 Total Assets: Money market funds $ 2 $ — $ — $ 2 Cash in savings account — — — 1,610 Cash in checking account — — — 223 Total cash and cash equivalents $ 2 $ — $ — $ 1,835 As of December 31, 2022 Level 1 Level 2 Level 3 Total Assets: Money market funds $ 6,893 $ — $ — $ 6,893 Cash in checking account — — — 470 Total cash and cash equivalents $ 6,893 $ — $ — $ 7,363

Note 4 - Property and Equipment

Note 4 - Property and Equipment, Net	9 Months Ended
	Sep. 30, 2023
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): September 30, December 31, 2023 2022 Computer equipment and software $ 161 $ 161 Laboratory and manufacturing equipment 574 575 Furniture and fixtures 27 27 Leasehold improvements 26 26 Property and equipment, gross 788 789 Less accumulated depreciation (674 ) (619 ) Property and equipment, net $ 114 $ 170 Depreciation expense totaled $21,000 and $64,000 for the three and nine months ended September 30, 2023, respectively. Depreciation expense totaled $29,000 and $61,000 for the three and nine months ended September 30, 2022, respectively.

Note 5 - Operating Lease Right-

Note 5 - Operating Lease Right-of-use Asset, Net	9 Months Ended
	Sep. 30, 2023
Notes to Financial Statements
Lessee, Operating Leases [Text Block]	(5) Operating Lease Right-of-Use Asset, Net In December 2021, we entered into a lease related to a property lease for our laboratory and corporate offices, which expires in January 2027, with an option for us to extend a further 36 months after expiration. Our lease agreements do not contain any material residual guarantees or material restrictive covenants. We determine 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. Right-of-use (ROU) assets and lease liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. Our lease does not provide an implicit rate. We used an adjusted historical incremental borrowing rate, based on the information available at the approximate lease commencement date, to determine the present value of lease payments. Variable rent expense is made up of expenses for common area maintenance and shared utilities and were not included in the determination of the present value of lease payments. We have no finance leases. Our lease expense was $121,000 and $362,000 for the three and nine months ended September 30, 2023, respectively. Our lease expense for the three and nine months ended September 30, 2022 was $121,000 and $362,000, respectively. The cash paid under the operating lease for base rent for the three and nine months ended September 30, 2023 was $117,000 and $353,000, respectively. The cash paid under the operating lease for base rent for the three and nine months ended September 30, 2022 was $114,000 and $287,000, respectively. On September 30, 2023, the weighted average remaining lease term was 3.59 years, and the weighted average discount rate was 10.74%. Future minimum lease payments under the operating lease as of September 30, 2023 were as follows (in thousands): Remainder of 2023 $ 118 2024 485 2025 499 2026 514 2027 44 Total undiscounted lease payments $ 1,660 Less imputed interest 262 Total operating lease liabilities $ 1,398

Note 6 - Accrued Expenses and O

Note 6 - Accrued Expenses and Other Current Liabilities	9 Months Ended
	Sep. 30, 2023
Notes to Financial Statements
Accrued Liabilities and Other Current Liabilities Disclosure [Text Block]	(6) Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following (in thousands): September 30, December 31, 2023 2022 Accrued expenses $ 36 $ 157 Accrued salaries and employee benefits 797 899 Accrued clinical trial costs 1,032 548 Grant liability 491 534 Customer deposits 90 90 Payable to related party 56 18 Total $ 2,502 $ 2,246

Note 7 - Stockholders' Equity

Note 7 - Stockholders' Equity	9 Months Ended
	Sep. 30, 2023
Notes to Financial Statements
Equity [Text Block]	(7) Stockholders Equity Warrants Number of Weighted Common Stock Average Warrants Exercise Price Balance as of December 31, 2022 2,424,724 $ 6.36 Warrants for common stock sold — — Warrants for common stock exercised — — Balance as of September 30, 2023 2,424,724 $ 6.36 June 2023 Financing - Cantor Fitzgerald Sales agreement - During the three and nine months ended September 30, 2023, we sold 33,282 and 168,122 shares of common stock under the ATM Offering at then-market prices for total gross proceeds of approximately $92,000 and $395,000, with net issuance costs of approximately $48,000 and $90,000, respectively. During the three months ended September 30, 2022, we sold 66,704 shares of common stock under the ATM Offering at then-market prices for total gross proceeds of $139,000, with a net refund of issuance costs of $1,000. During the nine months ended September 30, 2022, we sold 641,704 shares of common stock under the ATM Offering at then-market prices for total gross proceeds of approximately $1.7 million, with associated issuance costs of $231,000. Lincoln Park Capital stock purchase agreement - Pursuant to the Purchase Agreement in March 2021, 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 (Initial Purchase) and we 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 million purchase. On June 30, 2023, we provided notice to Lincoln Park of our election to terminate the Purchase Agreement. Following such termination, which was effective July 3, 2023, we may not sell any further shares of our common stock under the Purchase Agreement. As of the effective date of termination of the Purchase Agreement, we had not sold any common stock to Lincoln Park under the Purchase Agreement other than the Initial Purchase.

Note 8 - Share-based Compensati

Note 8 - Share-based Compensation	9 Months Ended
	Sep. 30, 2023
Notes to Financial Statements
Share-Based Payment Arrangement [Text Block]	(8) Share-Based Compensation The share-based compensation expense is recorded in research and development, and selling, general and administrative expenses based on the employee's or non-employee’s respective function. No share-based compensation was capitalized during the periods presented. Share-based compensation expense for the three and nine months ended September 30, 2023 and 2022 was recorded as follows (in thousands): Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Research and development $ 118 $ 132 $ 391 $ 389 Selling, general and administrative 133 148 455 514 Total share-based compensation $ 251 $ 280 $ 846 $ 903 The following table summarizes the activity of stock options and related information: Options outstanding Number of shares Weighted average exercise price Weighted average remaining contractual term (years) Aggregate intrinsic value (in thousands) Balance, December 31, 2022 2,182,708 $ 4.04 7.5 $ 343 Stock options granted 543,513 1.69 Stock options exercised (199 ) 1.49 Stock options forfeited (275,662 ) 2.15 Stock options expired (6,349 ) 16.09 Balance, September 30, 2023 2,444,011 $ 3.70 6.7 $ — Exercisable, September 30, 2023 1,558,484 $ 4.61 5.5 $ — Unrecognized share-based compensation for employee and nonemployee options granted through September 30, 2023 is approximately $1.6 million to be recognized over a remaining weighted average service period of 2.5 years. Share-Based Compensation (RSUs) The following summarizes the activity of non-vested RSUs: Weighted average grant date Number of fair value shares per share Balance, December 31, 2022 21,526 $ 4.33 RSUs granted 331,552 1.70 RSUs released (241,197 ) 1.93 RSUs forfeited (111,881 ) 1.70 Balance, September 30, 2023 — $ n/a RSUs vested and settled are converted into our common stock on a one-for-one basis. RSUs are generally subject to forfeiture if employment terminates prior to the release of vesting restrictions. The related compensation expense, which is based on the grant date fair value of our common stock multiplied by the number of units granted, is recognized ratably over the period during which the vesting restrictions lapse. Unrecognized share-based compensation for employee and nonemployee RSUs granted through September 30, 2023 was $0.

Note 9 - Net Loss Per Share

Note 9 - Net Loss Per Share	9 Months Ended
	Sep. 30, 2023
Notes to Financial Statements
Earnings Per Share [Text Block]	(9) 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 difference in the number of shares used to calculate basic and diluted shares outstanding since the effects of potentially dilutive securities are antidilutive due to the net loss position. The following 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: September 30, 2023 2022 Stock options to purchase common stock 2,444,011 2,148,732 Unvested restricted stock units — 2,734 Common stock warrants 2,424,724 2,424,724 Total 4,868,735 4,576,190

Note 10 - Income Taxes

Note 10 - Income Taxes	9 Months Ended
	Sep. 30, 2023
Notes to Financial Statements
Income Tax Disclosure [Text Block]	(10) Income Taxes During the three and nine months ended September 30, 2023 and 2022, there was no As of September 30, 2023, we retain a full valuation allowance on our deferred tax assets in all jurisdictions. The realization of our deferred tax assets depends primarily on our ability to generate future taxable income which is uncertain. We do not believe that our deferred tax assets are realizable on a more-likely-than-not basis; therefore, the net deferred tax assets have been fully offset by a valuation allowance.

Note 11 - Related Party Transac

Note 11 - Related Party Transactions	9 Months Ended
	Sep. 30, 2023
Notes to Financial Statements
Related Party Transactions Disclosure [Text Block]	(11) Related Party Transactions On April 9, 2020, we entered into a Litigation Funding Agreement (Funding Agreement) with BSLF, L.L.C. (Funder), an entity owned and controlled by Andrew Blank, Chair of BioCardia’s board of directors, for the purpose of funding our legal proceedings and any and all claims, actions and/or proceedings relating to or arising from the case captioned Boston Scientific Corp., et al., v. BioCardia Inc., Case No. 3:19-05645-VC, U.S.D.C., N. D. Cal (the Litigation). On April 12, 2021, all parties to the Litigation entered into a confidential settlement agreement and all claims were dismissed. In March 2022, we entered into confidential settlement agreements with our litigation service providers and the Funder to terminate the Funding Agreement and conclude all remaining matters thereunder (the Litigation Funding Settlement). Under the terms of the Litigation Funding Settlement, litigation and corporate counsel provided credits and refunds of legal fees totaling $688,000, which offset the amounts owed to us by the Funder under the Funding Agreement, and provided up to $300,000 in future discounts on legal services. As a result of the Litigation Funding Settlement, we will remit the discounts, as received, to the Funder on a quarterly basis. During the three and nine months ended September 30, 2023, we received discounts totaling $57,000 and $110,000, respectively. During the three and nine months ended September 30, 2022, we received discounts totaling $14,000 and $61,000, respectively. As of September 30, 2023 and December 31, 2022, we recorded a related party payable for discounts owed to the Funder in accrued expenses and other current liabilities of $56,000 and $18,000, respectively. As of September 30, 2023, up to $112,000 of future potential discounts are due to the Funder.

Note 12 - Contingencies and Unc

Note 12 - Contingencies and Uncertainties	9 Months Ended
	Sep. 30, 2023
Notes to Financial Statements
Contingencies Disclosure [Text Block]	(12) Contingencies and Uncertainties Contingencies Uncertainties

Significant Accounting Policies

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	(a) Basis of Preparation The accompanying condensed consolidated balance sheets, statements of operations, stockholders’ equity (deficit), and cash flows as of September 30, 2023, and for the three and nine months ended September 30, 2023 and 2022 are unaudited. The condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (U.S. GAAP) and applicable rules and regulations of the Securities and Exchange Commission (SEC) for interim financial information and on a basis consistent with the annual financial statements and, in the opinion of management, reflect all adjustments which include only normal recurring adjustments, necessary to present fairly our financial position as of September 30, 2023, results of operations for the three and nine months ended September 30, 2023 and 2022, and cash flows for the nine months ended September 30, 2023 and 2022. The results for the three and nine months ended September 30, 2023 are not necessarily indicative of the results to be expected for the year ended December 31, 2023 or for any other interim period or for any other future year. These condensed consolidated financial statements should be read in conjunction with the audited financial statements and related notes included in our Annual Report on Form 10-K for the year ended December 31, 2022, filed with the SEC on March 29, 2023.
Going Concern and Liquidity [Policy Text Block]	(b) Liquidity Going Concern We have incurred net losses and negative cash flows from operations since our inception and had an accumulated deficit of approximately $150.1 million as of September 30, 2023. Management expects operating losses and negative cash flows to continue through at least the next several years. We expect to incur increasing costs as we advance our trials and development activities. Therefore, absent additional funding, management believes cash and cash equivalents of $1.8 million as of September 30, 2023 are not sufficient to fund our planned expenditures and meet our obligations beyond January 2024. These factors raise substantial doubt about our ability to continue as a going concern beyond one year from the date these financial statements are issued. The financial statements do not include any adjustments that might result from the outcome of this uncertainty. Our ability to continue as a going concern and to continue further development of our therapeutic candidates beyond January 2024 will require us to raise additional capital. We plan to raise additional capital, potentially including debt and equity arrangements, to finance our future operations. The Company has also taken steps to reduce operating expenses to extend the cash runway. While we believe the plan to raise additional funds will alleviate the conditions that raise substantial doubt, the plan is not entirely within our control and cannot be assessed as being probable of occurring. If adequate funds are not available, we may be required to further reduce operating expenses, delay or reduce the scope of our product development programs, obtain funds through arrangements with others that may require us to relinquish rights to certain of our technologies or products that we would otherwise seek to develop or commercialize, or cease operations.
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.
Consolidation, Policy [Policy Text Block]	(d) Principles of Consolidation The condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary, BioCardia Lifesciences, Inc. All intercompany accounts and transactions have been eliminated during the consolidation process.
Concentration Risk, Credit Risk, Policy [Policy Text Block]	(e) Concentration of Credit Risk Financial instruments that potentially subject us to a concentration of credit risk consist of cash and cash equivalents. Our cash at times exceeds federally insured limits of $250,000 per customer. On September 30, 2023, approximately 98% of our cash and cash equivalents were held by one financial institution and total amounts on deposit were approximately $1.6 million in excess of FDIC insurance limits. We have not recognized any losses from credit risks on such accounts since inception.
Change to Significant Accounting Policies [Policy Text Block]	(f) Changes to Significant Accounting Policies Our significant accounting policies are described in Note 2 of the notes to the consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2022, filed with the SEC on March 29, 2023. There have been no changes to those policies.
New Accounting Pronouncements, Policy [Policy Text Block]	(g) Recent Accounting Pronouncements Recent accounting pronouncements issued by the Financial Accounting Standards Board (FASB), including its Emerging Issues Task Force, did not or are not believed by management to have a material impact on our financial statement presentation or disclosures.

Note 3 - Fair Value Measureme_2

Note 3 - Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2023
Notes Tables
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	As of September 30, 2023 Level 1 Level 2 Level 3 Total Assets: Money market funds $ 2 $ — $ — $ 2 Cash in savings account — — — 1,610 Cash in checking account — — — 223 Total cash and cash equivalents $ 2 $ — $ — $ 1,835 As of December 31, 2022 Level 1 Level 2 Level 3 Total Assets: Money market funds $ 6,893 $ — $ — $ 6,893 Cash in checking account — — — 470 Total cash and cash equivalents $ 6,893 $ — $ — $ 7,363

Note 4 - Property and Equipme_2

Note 4 - Property and Equipment, Net (Tables)	9 Months Ended
	Sep. 30, 2023
Notes Tables
Property, Plant and Equipment [Table Text Block]	September 30, December 31, 2023 2022 Computer equipment and software $ 161 $ 161 Laboratory and manufacturing equipment 574 575 Furniture and fixtures 27 27 Leasehold improvements 26 26 Property and equipment, gross 788 789 Less accumulated depreciation (674 ) (619 ) Property and equipment, net $ 114 $ 170

Note 5 - Operating Lease Righ_2

Note 5 - Operating Lease Right-of-use Asset, Net (Tables)	9 Months Ended
	Sep. 30, 2023
Notes Tables
Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block]	Remainder of 2023 $ 118 2024 485 2025 499 2026 514 2027 44 Total undiscounted lease payments $ 1,660 Less imputed interest 262 Total operating lease liabilities $ 1,398

Note 6 - Accrued Expenses and_2

Note 6 - Accrued Expenses and Other Current Liabilities (Tables)	9 Months Ended
	Sep. 30, 2023
Notes Tables
Schedule of Accrued Liabilities and Other Current Liabilities [Table Text Block]	September 30, December 31, 2023 2022 Accrued expenses $ 36 $ 157 Accrued salaries and employee benefits 797 899 Accrued clinical trial costs 1,032 548 Grant liability 491 534 Customer deposits 90 90 Payable to related party 56 18 Total $ 2,502 $ 2,246

Note 7 - Stockholders' Equity (

Note 7 - Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2023
Notes Tables
Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]	Number of Weighted Common Stock Average Warrants Exercise Price Balance as of December 31, 2022 2,424,724 $ 6.36 Warrants for common stock sold — — Warrants for common stock exercised — — Balance as of September 30, 2023 2,424,724 $ 6.36

Note 8 - Share-based Compensa_2

Note 8 - Share-based Compensation (Tables)	9 Months Ended
	Sep. 30, 2023
Notes Tables
Schedule of Share-based Compensation, Expense [Table Text Block]	Three months ended Nine months ended September 30, September 30, 2023 2022 2023 2022 Research and development $ 118 $ 132 $ 391 $ 389 Selling, general and administrative 133 148 455 514 Total share-based compensation $ 251 $ 280 $ 846 $ 903
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, 2022 2,182,708 $ 4.04 7.5 $ 343 Stock options granted 543,513 1.69 Stock options exercised (199 ) 1.49 Stock options forfeited (275,662 ) 2.15 Stock options expired (6,349 ) 16.09 Balance, September 30, 2023 2,444,011 $ 3.70 6.7 $ — Exercisable, September 30, 2023 1,558,484 $ 4.61 5.5 $ —
Schedule of Nonvested Restricted Stock Units Activity [Table Text Block]	Weighted average grant date Number of fair value shares per share Balance, December 31, 2022 21,526 $ 4.33 RSUs granted 331,552 1.70 RSUs released (241,197 ) 1.93 RSUs forfeited (111,881 ) 1.70 Balance, September 30, 2023 — $ n/a

Note 9 - Net Loss Per Share (Ta

Note 9 - Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2023
Notes Tables
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	September 30, 2023 2022 Stock options to purchase common stock 2,444,011 2,148,732 Unvested restricted stock units — 2,734 Common stock warrants 2,424,724 2,424,724 Total 4,868,735 4,576,190

Note 2 - Significant Accounti_2

Note 2 - Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Retained Earnings (Accumulated Deficit), Total	$ (150,103)	$ (140,604)
Cash and Cash Equivalents, at Carrying Value, Total	$ 1,835	$ 7,363
Cash, Percentage Held in One Financial Institution	98%
Cash, Uninsured Amount	$ 1,600

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 ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Total cash and cash equivalents	$ 1,835	$ 7,363
Fair Value, Inputs, Level 1 [Member]
Total cash and cash equivalents	2	6,893
Fair Value, Inputs, Level 2 [Member]
Total cash and cash equivalents	0	0
Fair Value, Inputs, Level 3 [Member]
Total cash and cash equivalents	0	0
Money Market Funds [Member]
Total cash and cash equivalents	2	6,893
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Total cash and cash equivalents	2	6,893
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Total cash and cash equivalents	0	0
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Total cash and cash equivalents	0	0
Demand Deposits [Member]
Total cash and cash equivalents	223	470
Demand Deposits [Member] | Fair Value, Inputs, Level 1 [Member]
Total cash and cash equivalents	0	0
Demand Deposits [Member] | Fair Value, Inputs, Level 2 [Member]
Total cash and cash equivalents	0	0
Demand Deposits [Member] | Fair Value, Inputs, Level 3 [Member]
Total cash and cash equivalents	0	$ 0
Savings Account [Member]
Total cash and cash equivalents	1,610
Savings Account [Member] | Fair Value, Inputs, Level 1 [Member]
Total cash and cash equivalents	0
Savings Account [Member] | Fair Value, Inputs, Level 2 [Member]
Total cash and cash equivalents	0
Savings Account [Member] | Fair Value, Inputs, Level 3 [Member]
Total cash and cash equivalents	$ 0

Note 4 - Property and Equipme_3

Note 4 - Property and Equipment, Net (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Depreciation	$ 21,000	$ 29,000	$ 64,000	$ 61,000

Note 4 - Property and Equipme_4

Note 4 - Property and Equipment, Net - Summary of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Property and equipment, gross	$ 788	$ 789
Less accumulated depreciation	(674)	(619)
Property and equipment, net	114	170
Computer Equipment and Software [Member]
Property and equipment, gross	161	161
Laboratory and Manufacturing Equipment [Member]
Property and equipment, gross	574	575
Furniture and Fixtures [Member]
Property and equipment, gross	27	27
Leasehold Improvements [Member]
Property and equipment, gross	$ 26	$ 26

Note 5 - Operating Lease Righ_3

Note 5 - Operating Lease Right-of-use Asset, Net (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Operating Lease, Expense	$ 121,000	$ 121,000	$ 362,000	$ 362,000
Operating Lease, Payments	$ 117,000	$ 114,000	$ 353,000	$ 287,000
Operating Lease, Weighted Average Remaining Lease Term	3 years 7 months 2 days		3 years 7 months 2 days
Operating Lease, Weighted Average Discount Rate, Percent	10.74%		10.74%

Note 5 - Operating Lease Righ_4

Note 5 - Operating Lease Right-of-use Asset, Net - Future Minimum Lease Payments Under Operating Lease (Details) $ in Thousands	Sep. 30, 2023 USD ($)
Remainder of 2023	$ 118
2024	485
2025	499
2026	514
2027	44
Total undiscounted lease payments	1,660
Less imputed interest	262
Total operating lease liabilities	$ 1,398

Note 6 - Accrued Expenses and_3

Note 6 - Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Accrued expenses	$ 36	$ 157
Accrued salaries and employee benefits	797	899
Accrued clinical trial costs	1,032	548
Grant liability	491	534
Customer deposits	90	90
Total	2,502	2,246
Related Party [Member]
Payable to related party	$ 56	$ 18

Note 7 - Stockholders' Equity_2

Note 7 - Stockholders' Equity (Details Textual) - USD ($)					3 Months Ended		9 Months Ended
	Sep. 30, 2023	Jun. 21, 2023	Apr. 12, 2022	Mar. 29, 2021	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Proceeds from Issuance of Common Stock							$ 3,042,000	$ 1,658,000
Payments of Stock Issuance Costs							$ 435,000	$ 231,000
Underwriters [Member]
Stock Issued During Period, Shares, New Issues (in shares)				80,000
June 2023 Financing [Member]
Stock Issued During Period, Shares, New Issues (in shares)		1,133,141
Shares Issued, Price Per Share (in dollars per share)		$ 2.336
Proceeds from Issuance of Common Stock		$ 2,600,000
Payments of Stock Issuance Costs		$ 194,000
June 2023 Financing [Member] | Company’s Directors and Executive Officers [Member]
Stock Issued During Period, Shares, New Issues (in shares)		203,337
Sales Agreement with Cantor Fitzgerald Co (Cantor) [Member]
Stock Issued During Period, Shares, New Issues (in shares)					33,282	66,704	168,122	641,704
Proceeds from Issuance of Common Stock					$ 92,000	$ 139,000	$ 395,000	$ 1,700,000
Payments of Stock Issuance Costs					$ 48,000	$ 1,000	$ 90,000	$ 231,000
Sale of Stock, Aggregate Value, Maximum	$ 8,300,000		$ 10,500,000
Accrued Sales Commission, Current, Percentage			3%
Purchase Agreement with Lincoln Park [Member]
Stock Issued During Period, Shares, New Issues (in shares)				373,832
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				5,000

Note 7 - Stockholders' Equity -

Note 7 - Stockholders' Equity - Warrants (Details)	9 Months Ended
	Sep. 30, 2023 $ / shares shares
Balance , number of common stock warrants (in shares) | shares	2,424,724
Balance, weighted average exercise price (in dollars per share) | $ / shares	$ 6.36
Warrants for common stock sold , number of common stock warrants (in shares) | shares	0
Warrants for common stock sold, weighted average exercise price (in dollars per share) | $ / shares	$ 0
Warrants for common stock exercised , number of common stock warrants (in shares) | shares	0
Warrants for common stock exercised, weighted average exercise price (in dollars per share) | $ / shares	$ 0
Balance , number of common stock warrants (in shares) | shares	2,424,724
Balance as, weighted average exercise price (in dollars per share) | $ / shares	$ 6.36

Note 8 - Share-based Compensa_3

Note 8 - Share-based Compensation (Details Textual) $ in Thousands	9 Months Ended
	Sep. 30, 2023 USD ($)
Restricted Stock Units (RSUs) [Member]
Share-Based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount	$ 0
Employees, Non-employees and Non-employee Directors [Member]
Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount	$ 1,600
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	2 years 6 months

Note 8 - Share-based Compensa_4

Note 8 - Share-based Compensation - Share-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Total share-based compensation	$ 251	$ 280	$ 846	$ 903
Research and Development Expense [Member]
Total share-based compensation	118	132	391	389
Selling, General and Administrative Expenses [Member]
Total share-based compensation	$ 133	$ 148	$ 455	$ 514

Note 8 - Share-based Compensa_5

Note 8 - Share-based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Balance, number of shares (in shares)	2,182,708
Balance, weighted average exercise price (in dollars per share)	$ 4.04
Balance, weighted average remaining contractual term (Year)	6 years 8 months 12 days	7 years 6 months
Balance, aggregate intrinsic value	$ 0	$ 343
Stock options granted, number of shares (in shares)	543,513
Stock options granted, weighted average exercise price (in dollars per share)	$ 1.69
Stock options exercised, number of shares (in shares)	(199)
Stock options exercised, weighted average exercise price (in dollars per share)	$ 1.49
Stock options forfeited, number of shares (in shares)	(275,662)
Stock options forfeited, weighted average exercise price (in dollars per share)	$ 2.15
Stock options expired, number of shares (in shares)	(6,349)
Stock options expired, weighted average exercise price (in dollars per share)	$ 16.09
Balance, number of shares (in shares)	2,444,011	2,182,708
Balance, weighted average exercise price (in dollars per share)	$ 3.70	$ 4.04
Exercisable, number of shares (in shares)	1,558,484
Exercisable, weighted average exercise price (in dollars per share)	$ 4.61
Exercisable, weighted average remaining contractual term (Year)	5 years 6 months
Exercisable, aggregate intrinsic value	$ 0

Note 9 - Share-based Compensati

Note 9 - Share-based Compensation - Summary of Non-vested RSUs (Details) - Restricted Stock Units (RSUs) [Member] - $ / shares	9 Months Ended
	Sep. 30, 2023	Jan. 01, 2023
Balance, number of shares (in shares)	21,526
Balance, weighted average grant date fair value per share (in dollars per share)		$ 4.33
RSUs granted, number of shares (in shares)	331,552
RSUs granted, weighted average grant date fair value per share (in dollars per share)	$ 1.70
RSUs released, number of shares (in shares)	(241,197)
RSUs released, weighted average grant date fair value per share (in dollars per share)	$ 1.93
RSUs forfeited, number of shares (in shares)	(111,881)
RSUs forfeited, weighted average grant date fair value per share (in dollars per share)	$ 1.70
Balance, number of shares (in shares)	0

Note 9 - Net Loss Per Share - A

Note 9 - Net Loss Per Share - Anti-dilutive Securities (Details) - shares	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Antidilutive securities (in shares)	4,868,735	4,576,190
Share-Based Payment Arrangement, Option [Member]
Antidilutive securities (in shares)	2,444,011	2,148,732
Restricted Stock Units (RSUs) [Member]
Antidilutive securities (in shares)	0	2,734
Warrant [Member]
Antidilutive securities (in shares)	2,424,724	2,424,724

Note 10 - Income Taxes (Details

Note 10 - Income Taxes (Details Textual) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Income Tax Expense (Benefit)	$ 0	$ 0

Note 11 - Related Party Trans_2

Note 11 - Related Party Transactions (Details Textual) - Funding Agreement [Member] - BSLF, L.L.C. [Member] - USD ($)	1 Months Ended		3 Months Ended		9 Months Ended
	Mar. 31, 2022	Mar. 29, 2022	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Legal Fees	$ 688,000
Maximum Discount on Legal Service		$ 300,000
Litigation Service, Expense			$ 57,000	$ 14,000	$ 110,000	$ 61,000
Other Liabilities, Current			56,000		56,000		$ 18,000
Loss Contingency Accrual			$ 112,000		$ 112,000