Pulse Biosciences (PLSE) 10-K 31 Mar 23 2022 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2022	Mar. 27, 2023	Jun. 30, 2022
Document Information [Line Items]
Entity Central Index Key	0001625101
Entity Registrant Name	Pulse Biosciences, Inc.
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2022
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2022
Document Transition Report	false
Entity File Number	001-34899
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-5696597
Entity Address, Address Line One	3957 Point Eden Way
Entity Address, City or Town	Hayward
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94545
City Area Code	510
Local Phone Number	906-4600
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	PLSE
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 23,793,458
Entity Common Stock, Shares Outstanding		37,592,588
Auditor Firm ID	34
Auditor Name	Deloitte & Touche LLP
Auditor Location	San Jose, California

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 61,139	$ 28,614
Accounts receivable	0	61
Inventory	0	5,824
Prepaid expenses and other current assets	1,008	2,131
Total current assets	62,147	36,630
Property and equipment, net	1,961	2,462
Intangible assets, net	2,551	3,216
Goodwill	2,791	2,791
Right-of-use assets	8,062	8,785
Other assets	365	365
Total assets	77,877	54,249
Current liabilities:
Accounts payable	1,573	2,904
Accrued expenses	2,595	4,389
Deferred revenue	0	16
Lease liability, current	896	774
Note payable, current	0	436
Related party note payable, current	917	0
Total current liabilities	5,981	8,519
Lease liability, less current portion	9,144	10,040
Related party note payable, less current	65,000	0
Total liabilities	80,125	18,559
Commitments and contingencies (Note 13)
Stockholders’ equity:
Preferred stock, $0.001 par value; authorized – 50,000 shares; no shares issued and outstanding	0	0
Common stock, $0.001 par value; authorized – 500,000 shares; issued and outstanding – 37,235 shares and 29,716 shares at December 31, 2022 and 2021, respectively	37	29
Additional paid-in capital	292,420	271,861
Accumulated other comprehensive income (loss)	0	0
Accumulated deficit	(294,705)	(236,200)
Total stockholders’ (deficit) equity	(2,248)	35,690
Total liabilities and stockholders’ equity	$ 77,877	$ 54,249

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
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)	500,000,000	500,000,000
Common stock, shares issued (in shares)	37,235,000	29,716,000
Common stock, shares outstanding (in shares)	37,235,000	29,716,000

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenues:
Total revenues	$ 700	$ 1,418	$ 0
Cost and expenses:
Cost of revenues	11,944	1,968	0
Research and development	20,839	28,640	26,444
Sales and marketing	12,019	14,751	7,256
General and administrative	13,955	19,073	16,265
Total cost and expenses	58,757	64,432	49,965
Loss from operations	(58,057)	(63,014)	(49,965)
Other income (expense):
Interest income (expense), net	(448)	(646)	114
Total other income (expense)	(448)	(646)	114
Loss from operations, before income taxes	(58,505)	(63,660)	(49,851)
Income tax benefit	0	0	0
Net loss	(58,505)	(63,660)	(49,851)
Other comprehensive gain (loss):
Unrealized gain (loss) on available-for-sale securities	0	1	(5)
Comprehensive loss	$ (58,505)	$ (63,659)	$ (49,856)
Net loss per share:
Basic and diluted net loss per share (in dollars per share)	$ (1.72)	$ (2.28)	$ (2.14)
Weighted average shares used to compute net loss per common share — basic and diluted (in shares)	33,935	27,964	23,248
Product [Member]
Revenues:
Total revenues	$ 700	$ 1,418	$ 0

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Rights Offering [Member] Common Stock [Member]	Rights Offering [Member] Additional Paid-in Capital [Member]	Rights Offering [Member] AOCI Attributable to Parent [Member]	Rights Offering [Member] Retained Earnings [Member]	Rights Offering [Member]	Private Placement [Member] Common Stock [Member]	Private Placement [Member] Additional Paid-in Capital [Member]	Private Placement [Member] AOCI Attributable to Parent [Member]	Private Placement [Member] Retained Earnings [Member]	Private Placement [Member]	ATM Offering [Member] Common Stock [Member]	ATM Offering [Member] Additional Paid-in Capital [Member]	ATM Offering [Member] AOCI Attributable to Parent [Member]	ATM Offering [Member] Retained Earnings [Member]	ATM Offering [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2019																20,825,000
Balance at Dec. 31, 2019																$ 21	$ 153,401	$ 4	$ (122,689)	$ 30,737
Issuance of common stock upon exercise of stock options (in shares)																175,000
Issuance of common stock upon exercise of stock options																$ 0	887	0	0	887
Issuance of shares under employee stock purchase plan (in shares)																83,000
Issuance of shares under employee stock purchase plan																$ 0	490	0	0	490
Issuance of shares upon exercise of warrants (in shares)																187,000
Issuance of shares upon exercise of warrants																$ 0	1,127	0	0	1,127
Issuance of common stock, shares (in shares)	4,280,000
Issuance of common stock	$ 4	$ 29,430	$ 0	$ 0	$ 29,434
Stock-based compensation expense																0	10,075	0	0	10,075
Unrealized gain (loss) on available-for-sale securities																0	0	(5)	0	(5)
Net loss																$ 0	0	0	(49,851)	(49,851)
Balance (in shares) at Dec. 31, 2020																25,550,000
Balance at Dec. 31, 2020																$ 25	195,410	(1)	(172,540)	22,894
Issuance of common stock upon exercise of stock options (in shares)																54,000
Issuance of common stock upon exercise of stock options																$ 0	616	0	0	616
Issuance of shares under employee stock purchase plan (in shares)																91,000
Issuance of shares under employee stock purchase plan																$ 0	810	0	0	810
Issuance of shares upon exercise of warrants (in shares)																585,000
Issuance of shares upon exercise of warrants																$ 1	3,333	0	0	3,334
Issuance of common stock, shares (in shares)											288,000				288,490
Issuance of common stock											$ 0	$ 7,432	$ 0	$ 0	$ 7,432
Stock-based compensation expense																0	14,601	0	0	14,601
Unrealized gain (loss) on available-for-sale securities																0	0	1	0	1
Net loss																$ 0	0	0	(63,660)	(63,660)
Issuance of common stock as part of debt extinguishment and private investment, net of issuance cost of $106 (in shares)						3,049,000
Issuance of common stock as part of debt extinguishment and private investment, net of issuance cost of $106						$ 3	$ 49,891	$ 0	$ 0	$ 49,894
Issuance of common stock upon vesting of restricted stock units, net of shares withheld for employee taxes (in shares)																99,000
Issuance of common stock upon vesting of restricted stock units, net of shares withheld for employee taxes																$ 0	(232)	0	0	(232)
Balance (in shares) at Dec. 31, 2021																29,716,000
Balance at Dec. 31, 2021																$ 29	271,861	0	(236,200)	35,690
Issuance of shares under employee stock purchase plan (in shares)																188,000
Issuance of shares under employee stock purchase plan																$ 1	485	0	0	486
Issuance of shares upon exercise of warrants (in shares)																14,000
Issuance of shares upon exercise of warrants																$ 0	26	0	0	26
Issuance of common stock, shares (in shares)	7,317,000
Issuance of common stock	$ 7	$ 14,857	$ 0	$ 0	$ 14,864
Stock-based compensation expense																0	5,191	0	0	5,191
Unrealized gain (loss) on available-for-sale securities																				0
Net loss																$ 0	0	0	(58,505)	(58,505)
Balance (in shares) at Dec. 31, 2022																37,235,000
Balance at Dec. 31, 2022																$ 37	$ 292,420	$ 0	$ (294,705)	$ (2,248)

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Rights Offering [Member]
Offering price per unit (in dollars per share)			$ 7.01
Issuance cost	$ 136		$ 565
Private Placement [Member]
Issuance cost		$ 106
ATM Offering [Member]
Issuance cost		$ 568

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net loss	$ (58,505)	$ (63,660)	$ (49,851)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	690	480	430
Amortization of intangible assets	665	666	665
Stock-based compensation	5,191	14,601	10,075
Write-off of excessive and obsolete inventory	8,477	0	0
Net premium amortization and discount on available-for-sale securities	0	13	5
Loss on disposal of fixed assets	185	0	119
Gain on U.S. Treasury securities	0	0	(8)
Changes in operating assets and liabilities:
Accounts receivable	61	(61)	0
Inventory	(2,653)	(5,824)	0
Prepaid expenses and other current assets	1,164	(1,374)	194
Other receivables	(41)	54	0
Right-of-use assets	723	653	509
Other long-term assets	0	0	129
Accounts payable	(1,304)	1,160	(266)
Accrued expenses	(1,794)	(937)	2,830
Deferred revenue	(16)	16	0
Lease liabilities	(774)	(542)	(196)
Accrued interest on related party note payable	917	0	0
Accrued interest on note payable	1	658	0
Net cash used in operating activities	(47,013)	(54,097)	(35,365)
Cash flows from investing activities:
Purchases of property and equipment	(401)	(437)	(441)
Purchases of investments	0	0	(29,025)
Maturities of investments	0	8,000	35,000
Sales of investments	0	0	4,510
Net cash provided by (used in) investing activities	(401)	7,563	10,044
Cash flows from financing activities:
Proceeds from issuance of common stock under employee stock purchase plan	486	810	490
Proceeds from exercises of warrants	26	4,217	244
Proceeds from exercises of stock options	0	786	717
Proceeds from issuance of common stock	14,864	56,697	29,434
Proceeds from issuance of related party note	65,000	0	0
Proceeds from insurance loan agreement	0	1,939	0
Payments made on insurance loan agreement	(437)	(1,532)	0
Tax payments related to shares withheld for vested restricted stock units	0	(232)	0
Net cash provided by financing activities	79,939	62,685	30,885
Net increase in cash and cash equivalents	32,525	16,151	5,564
Cash and cash equivalents at beginning of period	28,614	12,463	6,899
Cash and cash equivalents at end of period	61,139	28,614	12,463
Supplemental disclosure of noncash investing and financing activities:
Other receivable from exercise of warrants and stock options	0	0	1,053
Change in unrealized gains on available-for-sale securities	0	1	(5)
Equipment purchases included in accounts payable and accrued expenses	(27)	(27)	(20)
Equipment purchases included in accounts payable and accrued expenses	27	27	20
Accrued interest settled via issuance of common stock from private placement equity offering	$ 0	$ 629	$ 0

Note 1 - Description of Busines

Note 1 - Description of Business	12 Months Ended
	Dec. 31, 2022
Notes to Financial Statements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	1. Pulse Biosciences, Inc. is a novel bioelectric medicine company committed to health innovation using its patented Nano-Pulse Stimulation (“NPS”) technology, a revolutionary energy modality that delivers nanosecond-duration pulses of electrical energy, each less than a millionth of a second 2022 The Company was incorporated in Nevada on May 19, 2014. June 18, 2018, The Company’s activities are subject to significant risks and uncertainties, including the need for additional capital. The Company does not no

Note 2 - Summary of Significant

Note 2 - Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2022
Notes to Financial Statements
Significant Accounting Policies [Text Block]	2. Basis of Presentation Certain prior period balances have been reclassified to conform to the current period presentation in the consolidated financial statements and the accompanying notes. Sales and marketing expenses are reclassified out of general and administrative expenses, both of which are presented as separate line items. Amortization of intangible assets are reclassified to general and administrative expenses. Principles of Consolidation The accompanying consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and pursuant to the rules and regulations of the United States Securities Exchange Commission (the “SEC”). The consolidated financial statements include the financial statements of the Company and its wholly-owned subsidiaries and intercompany balances and transactions have been eliminated in consolidation. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires the Company to make estimates that affect the amounts reported in the financial statements and accompanying notes to the financial statements. Estimates include, but are not Concentration of Credit Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents and investments. The Company places its cash equivalents and investments with high credit quality financial institutions and, by policy, limits the amounts invested with any one may not Fair Value of Financial Instruments The Company believes the carrying amounts of its financial instruments, including cash equivalents, prepaid expenses and other current assets, accounts payable and accrued expenses, approximate fair value due to the short-term nature of such instruments. Cash and Cash Equivalents The Company invests its cash primarily in money market funds. The Company considers all highly liquid investments purchased with an original maturity of three Property and Equipment Property and Equipment is recorded at cost and depreciated using the straight-line method over their estimated useful lives, ranging from three five Valuation of Inventory Inventory is stated at lower of cost or net realizable value. The Company establishes the inventory basis by determining the cost based on standard costs approximating the purchase costs on a first first December 31, 2022 Intangible Assets The Company’s intangible assets consist of acquired patents and licenses, which are amortized over their estimated useful lives of twelve Long-Lived Assets The Company reviews long-lived assets, consisting of property and equipment and intangible assets, for impairment during each fiscal year or when events or changes in circumstances indicate the carrying value of these assets may Goodwill The Company records goodwill when the consideration paid in a business acquisition exceeds the fair value of the net tangible assets and the identified intangible assets acquired. The Company reviews goodwill for impairment at the reporting unit level at least annually or whenever changes in circumstances indicate that the carrying value of the goodwill may not Revenue from Contracts with Customers The Company recognizes revenue at a point in time when it satisfies performance obligations by transferring control of promised goods to its customers. The amount of revenue recognized is equal to the consideration which the Company is entitled to in exchange for the promised goods, excluding any amounts assessed by government authorities for taxes which might be collected from a customer. Sales contracts often involve the sale and delivery of multiple products, each of which typically represent a separate performance obligation in the contract. While the Company sells these products on a stand-alone basis at their respective SSP, initial customer contracts will likely involve the bundling of products which will be delivered concurrently to the customer. In such instances, the full consideration of the contract will be recognized upon shipment of the products. The Company generally requires receipt of full payment prior to shipment, however, from time to time, payment terms may 9 Product Warranty The Company provides a standard warranty on eligible products which provides the customer assurances that the products comply with the agreed-upon specifications. The standard warranty does not may Warranty accrual activity consisted of the following (in thousands): Year Ended December 31, 2022 2021 Beginning balance $ 80 $ — Add: Accruals for warranties issued during the period 42 80 Less: Adjustment for inventory at cost and excessive and obsolete inventory (72 ) — Ending balance $ 50 $ 80 Stock-Based Compensation The Company recognizes the cost of stock-based compensation in the financial statements based upon fair value. The fair value of stock options is determined as of the grant date using the Black-Scholes option pricing model. The fair value of Restricted Stock Units (“RSU”) awards is determined based on the number of units granted and the closing price of the Company’s common stock on the grant date. The fair value of each purchase under the employee stock purchase plan (“ESPP”) is estimated at the beginning of the offering period using the Black-Scholes option pricing model. The Company’s determination of the fair value of equity-settled awards is impacted by the price of the Company’s common stock as well as changes in assumptions regarding a number of complex and subjective variables. These variables include, but are not Estimates of the fair value of equity-settled awards as of the grant date using valuation models, such as the Black-Scholes option pricing model, are affected by assumptions regarding a number of complex variables. Changes in the assumptions can materially affect the fair value of the award and the stock-based compensation expense recognized. These inputs are subjective and generally require significant analysis and judgment to develop. The Company determines the volatility factor based on its own historical volatility. The risk-free interest rate is based on the yield available on U.S. Treasury zero See Note 6 Research and Development Costs Research and development costs consist primarily of compensation costs, fees paid to consultants and outside service providers and organizations (including university research institutes), costs associated with clinical trials, development prototypes and other expenses relating to the acquisition, design, development and testing of the Company’s product candidates, and certain facilities related costs. Research and development costs incurred by the Company are expensed as incurred, unless the achievement of milestones, the completion of contracted work, or other information indicates that a different expensing schedule is more appropriate. Patent Costs The Company is the owner of numerous domestic and foreign patents. Due to the significant uncertainty associated with the successful development of one not December 31, 2022, 2021 2020 Income Taxes The Company accounts for income taxes under an asset and liability approach for financial accounting and reporting for income taxes. Accordingly, the Company recognizes deferred tax assets and liabilities for the expected impact of differences between the financial statements and the tax basis of assets and liabilities. The Company records a valuation allowance to reduce its deferred tax assets to the amount that is more-likely-than- not not The Company is subject to U.S. federal income taxes and state income taxes in various states. As the Company’s net operating losses have yet to be utilized, previous tax years remain open to examination by federal authorities and other jurisdictions in which the Company currently operates or has operated in the past. The Company is not The Company accounts for uncertainties in income tax law under a comprehensive model for the financial statement recognition, measurement, presentation and disclosure of uncertain tax positions taken or expected to be taken in income tax returns as prescribed by U.S. GAAP. The tax effects of a position are recognized only if it is more-likely-than- not not not no December 31, 2022 2021 not Comprehensive Loss Comprehensive loss consists of net loss and unrealized gains or losses on available-for-sale investments. The Company displays comprehensive loss and its components as part of the consolidated statements of operations and comprehensive loss. Net Loss per Share The Company calculates basic net loss per share by dividing net loss by the weighted average number of shares of common stock outstanding during the period. Diluted net loss per share is computed by giving effect to all potential dilutive common stock equivalents outstanding during the period. For purposes of this calculation, options to purchase common stock and common stock warrants are considered common stock equivalents. Potential common shares that have an anti-dilutive effect ( i.e. The following outstanding stock options, warrants, and RSUs to purchase common stock were excluded from the computation of diluted net loss per share for the periods presented because including them would have had an anti-dilutive effect: Year Ended December 31, 2022 2021 2020 Common stock warrants 7,303,832 — 612,310 Common stock options 5,250,696 5,996,813 5,039,194 Restricted stock units — — 111,305 Total 12,554,528 5,996,813 5,762,809 Segment and Geographical Information The Company operates in one segment and reports segment information in accordance with ASC 280 , Segment Reporting one not December 31, 2022 2021 , See Note 10 Recent Accounting Pronouncements In May 2014, No. 2014 09, Revenue from Contracts with Customers first 2018. 2021 9 In November 2018, No. 2018 18 Collaborative Arrangements Clarifying the Interaction between Topic 808 606 808, Collaborative Arrangements 606, Revenue from Contracts with Customers 606” 606 not January 1, 2020, not August 2021 not no In December 2019, 2019 12, Income Taxes (Topic 740 740 December 15, 2020, 740 January 1, 2021. not

Note 3 - Investments and Fair V

Note 3 - Investments and Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2022
Notes to Financial Statements
Fair Value Disclosures [Text Block]	3. Fair Value of Financial Instruments The Company determines the fair value of its financial instruments based on a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three Level 1 1 Level 2 1, 2 Level 3 no not 3 The following table sets forth the fair value of the Company’s financial assets measured on a recurring basis (in thousands): December 31, 2022 Assets Classification Level 1 Level 2 Level 3 Total Money market funds Cash and cash equivalents $ 57,973 $ — $ — $ 57,973 Total assets measured at fair value $ 57,973 $ — $ — $ 57,973 December 31, 2021 Assets Classification Level 1 Level 2 Level 3 Total Money market funds Cash and cash equivalents $ 23,675 $ — $ — $ 23,675 Total assets measured at fair value $ 23,675 $ — $ — $ 23,675 During the years ended December 31, 2022 2021 not December 31, 2022 2021 not 1, 2 3 not December 31, 2022 2021

Note 4 - Balance Sheet Componen

Note 4 - Balance Sheet Components	12 Months Ended
	Dec. 31, 2022
Notes to Financial Statements
Supplemental Balance Sheet Disclosures [Text Block]	4. Inventory Inventory consisted of the following (in thousands): Year Ended December 31, 2022 2021 Raw materials $ — $ 2,010 Work in process — 1,371 Finished goods — 2,443 Total inventory $ — $ 5,824 Property and Equipment, net Property and equipment, net consisted of the following (in thousands): December 31, 2022 2021 Leasehold improvements $ 2,519 $ 2,519 Laboratory equipment 1,118 1,019 Furniture, fixtures and equipment 966 932 Software 289 202 Construction in progress 22 186 4,914 4,858 Less: Accumulated depreciation and amortization (2,953 ) (2,396 ) $ 1,961 $ 2,462 Depreciation expense for the years ended December 31, 2022, 2021 2020 Intangible Assets, net Intangible assets primarily consist of a license to utilize certain patents, know-how and technology relating to the Company’s NPS for biomedical applications acquired from Old Dominion University Research Foundation (ODURF), Eastern Virginia Medical School (EVMS), and the University of Southern California. In addition, the Company entered into a sponsored research agreement (“SRA”) with Old Dominion University’s Frank Reidy Research Center for Bioelectrics, a leading research organization in the field, which includes certain intellectual property rights arising from the research. The Company is amortizing the intangible assets over an estimated useful life of 12 years. Intangible assets, net consisted of the following (in thousands): December 31, 2022 2021 Acquired patents and licenses $ 7,985 $ 7,985 Less: Accumulated amortization (5,434 ) (4,769 ) $ 2,551 $ 3,216 A schedule of the amortization of intangible assets is as follows (in thousands): Years ending December 31: 2023 $ 665 2024 665 2025 665 2026 556 $ 2,551 Accrued Expenses Accrued expenses consisted of the following (in thousands): December 31, 2022 2021 Compensation expense $ 1,377 $ 2,932 Controlled launch (Note 8) — 534 Director and officer liability insurance (Note 12) 571 — Clinical trial fees and costs 64 245 Professional fees 318 85 Warranty 50 80 Other 215 513 $ 2,595 $ 4,389

Note 5 - Goodwill

Note 5 - Goodwill	12 Months Ended
	Dec. 31, 2022
Notes to Financial Statements
Goodwill Disclosure [Text Block]	5. In 2014, 805, Business Combinations The Company reviews goodwill for impairment annually or whenever changes in circumstances indicate that the carrying amount of goodwill may not December 31, 2022 not

Note 6 - Stockholders' Equity a

Note 6 - Stockholders' Equity and Stock-based Compensation	12 Months Ended
	Dec. 31, 2022
Notes to Financial Statements
Share-Based Payment Arrangement [Text Block]	6. Equity and Stock-Based Compensation Preferred Stock The Company has authorized a total of 50,000,000 shares of preferred stock, par value $0.001 per share, none of which were outstanding at December 31, 2022 2021 Common Stock The Company has authorized a total of 500,000,000 shares of common stock, par value $0.001 per share. Rights Offering On June 9, 2022, “2022 one one “2022 one 2022 2022 2022 may 2022 2022 one 2022 fifth 2022 2022 not may not three 2022 Private Placement Securities Purchase Agreement On June 30, 2021, 13 July 2021. At-the-Market Equity Offering On February 4, 2021, may 415 1933, no December 31, 2022 not December 31, 2021 Common Stock Warrants In connection with a private placement in November 2014 seven March 2021, November 2021, In connection with the closing of the Company’s initial public offering in May 2016, five March 2021, May 2021, In connection with a June 2020 “2020 2020 fifth June 16, 2025, 2020 December 16, 2020, six not 2020 December 31, 2020, February 5, 2021, February 5, 2021 December 31, 2022 2020 In connection with the 2022 2022 2022 fifth 2022 2022 not may not three December 31, 2022 December 31, 2022 2022 A summary of total warrants activity for the year ended December 31, 2022 Weighted Average Weighted Remaining Number of Average Contractual Shares Exercise Price Life (in Years) Warrants outstanding at December 31, 2021 — $ — — Issued 7,317,072 2.05 Exercised (13,240 ) 2.05 Expired/Redeemed — — Warrants outstanding and exercisable at December 31, 2022 7,303,832 $ 2.05 4.43 Equity Plans 2017 2017 The Board previously adopted, and the Company’s stockholders approved, the Company’s 2017 “2017 The 2017 may 2017 2015 “2015 not 2017 2017 January 1, 2022 2021, 2017 2017 2017 December 31 December 31, 2022 2017 During November 2017, 2017 The Inducement Plan has a 10-year term and provides for the grant of equity-based awards, including non-statutory stock options, RSUs, restricted stock, stock appreciation rights, performance shares and performance units, and its terms are substantially similar to the 2017 may ten first not May 2021, December 31, 2022 A summary of stock option activity under the 2015 2017 December 31, 2022 Stock Options Outstanding Number of shares Weighted average exercise price Weighted average remaining life (in years) Balances — December 31, 2021 5,996,813 $ 15.77 7.33 Options granted 1,440,100 2.97 Options exercised — — Options canceled (1,472,385 ) 14.88 Options expired (713,832 ) 14.62 Balances — December 31, 2022 5,250,696 $ 12.67 6.24 Exercisable — December 31, 2022 3,479,531 $ 15.17 5.06 Time-based Options The Company awards time-based options which vest and become exercisable, subject to the individual’s continued employment or service through the applicable vesting date. Time-based options can have various vesting schedules, most commonly new hire grants which generally vest 25% per year starting upon the first A summary of the time-based stock option activity under the 2015 2017 December 31, 2022 Stock Options Outstanding Number of shares Weighted average exercise price Weighted average remaining life (in years) Balances — December 31, 2021 4,796,716 $ 16.44 7.05 Options granted 1,240,100 2.59 Options exercised — — Options canceled (674,465 ) 16.73 Options expired (631,957 ) 15.05 Balances — December 31, 2022 4,730,394 $ 12.95 6.16 Exercisable — December 31, 2022 3,230,670 $ 15.39 5.07 The intrinsic value of time-based options exercised during the years ended December 31, 2022, 2021 2020 The fair value of the time-based options granted to employees and directors during the years ended December 31, 2022, 2021 2020 Performance Options Certain stock options awarded to the Company’s executives and other employees contain performance conditions related to certain financial measures and achievements of strategic/operational milestones. The options will vest and become exercisable once the specific performance condition is fulfilled. A summary of the performance option activity under the 2017 December 31, 2022 Stock Options Outstanding Number of shares Weighted average exercise price Weighted average remaining life (in years) Balances — December 31, 2021 1,200,097 $ 13.11 8.44 Options granted 200,000 5.32 Options exercised — — Options canceled (797,920 ) 13.32 Options expired (81,875 ) 11.28 Balances — December 31, 2022 520,302 $ 10.08 7.02 Exercisable — December 31, 2022 248,861 $ 12.25 4.92 The fair value of the performance options granted to employees during the years ended December 31, 2022, 2021 2020 The fair value of employee stock options was estimated using the Black-Scholes option-pricing model utilizing the following assumptions: Year Ended December 31, 2022 2021 2020 Expected term in years 5.3 - 6.8 5.3 - 6.1 5.3 - 6.1 Expected volatility 83 88% 78% 70% Risk-free interest rate 1.9 - 3.2% 0.9 - 1.4% 0.3 - 0.5% Dividend yield — — — 2017 The Board previously adopted and the stockholders approved the Company’s 2017 “2017 The 2017 2017 2017 December 31 2020 not January 1, 2021, 2017 2017 December 31, 2022 2021 2017 December 31, 2022 2017 The fair value of ESPP was estimated using the Black-Scholes option-pricing model utilizing the following assumptions: Year Ended December 31, 2022 2021 2020 Expected term in years 0.5 - 1.0 0.5 - 1.0 0.5 - 1.0 Expected volatility 83% 78% 70 % Risk-free interest rate 0.6% - 3.5% 0.06% - 0.1% 0.1% - 1.0% Dividend yield — — — Restricted Stock Units The fair value of RSU awards is determined based on the number of units granted and the closing price of the Company’s common stock as of the grant date. The estimated fair value of RSUs is recognized on a straight-line basis over the requisite service period. During the year ended December 31, 2017, June 2018. 2019, 2021, December 31, 2022 December 31, 2022, 2021 2020 December 31, 2022 During the year ended December 31, 2017, June 1, 2019 June 1, 2021. December 31, 2022, 2021 2020 zero December 31, 2022 Stock-based Compensation Total stock-based compensation expense recorded in the consolidated statements of operations and comprehensive loss was as follows (in thousands): Year Ended December 31, 2022 2021 2020 Cost of revenues $ 217 $ 129 $ — Research and development 1,563 5,211 4,013 Sales and marketing 733 2,749 1,187 General and administrative 2,678 6,512 4,875 Total stock-based compensation expense $ 5,191 $ 14,601 $ 10,075 As of December 31, 2022 not In February 2021, not December 31, 2021 In October 2021, ninety ten may 2017 December 31, 2021. Total stock-based compensation expense by award type was as follows (in thousands): Year Ended December 31, 2022 2021 2020 Time-based options $ 4,467 $ 9,235 $ 8,739 Performance options 233 4,840 133 RSU — — 86 ESPP 491 526 1,117 Total stock-based compensation expense $ 5,191 $ 14,601 $ 10,075 At December 31, 2022

Note 7 - Research Grants and Ag

Note 7 - Research Grants and Agreements	12 Months Ended
	Dec. 31, 2022
Notes to Financial Statements
Research, Development, and Computer Software Disclosure [Text Block]	7. Sponsored Research Agreement The Company entered into a SRA with ODURF during 2014 August 2018, September 2019, 12 March 2021, May 2021 12 may December 31, 2022, 2021 2020 December 31, 2022 no

Note 8 - Controlled Launch

Note 8 - Controlled Launch	12 Months Ended
	Dec. 31, 2022
Notes to Financial Statements
Controlled Launch [Text Block]	8. In February 2021, 510 January 2021, June 2021 February 2021, June 2021, As part of the Controlled Launch, the Company selected 70 physicians and their practices to be the first As patient procedures and surveys were completed under the Controlled Launch program, the Company accrued the value of the credits earned, which were recorded in accrued expenses, with a corresponding charge to sales and marketing expense. During the years ended December 31, 2022 2021 During the year ended December 31, 2022, 9 In September 2022, fourth 2022

Note 9 - Revenue

Note 9 - Revenue	12 Months Ended
	Dec. 31, 2022
Notes to Financial Statements
Revenue from Contract with Customer [Text Block]	9. The Company recognizes revenue at a point in time when it satisfies performance obligations by transferring control of promised goods to its customers. The amount of revenue recognized is equal to the consideration which the Company is entitled to in exchange for the promised goods, excluding any amounts assessed by government authorities for taxes which might be collected from a customer. This consideration may September 20, 2022, December 31, 2022 2021 Sales contracts often involve the sale and delivery of multiple performance obligations in the contract. Performance Obligations Systems consist of the CellFX console and its embedded software, handpieces, and disposable tips. The console is a physical piece of hardware used by the customer to perform patient procedures. Individually the console and software are not one Handpieces are attached to the console and used in conjunction with tips to perform patient procedures. Generally, upon initial sale of a system to a customer, the Company will include two Disposable treatment tips are single-patient multiple-use products that come in different sizes, each of which are to be used for specific procedures. Tips are attached to the handpiece for use in patient procedures and, upon detachment from the handpiece, a tip cannot be reused, and it must be disposed of. Tips represent a distinct performance obligation which is satisfied either upon shipment, or upon delivery of the tips to the customer, depending on the specific contract. CUs are credits that authorize the customer to perform a procedure, or cycle. Each procedure requires a specific number of CUs, dependent upon type of tip used and procedure level selected. As the procedure is performed, the applicable number of CUs are decremented. When the customer’s balance of CUs on a specific system is depleted, the system will no not Shipping and handling activities are not Transaction Price The transaction price is the consideration to which the Company expects to be entitled to in exchange for providing the promised goods to customers. Customer orders placed for cash contemplate a fixed amount of consideration. Customer orders placed by physicians participating in the Controlled Launch when they elected to purchase the CellFX System were paid for via conversion of accumulated earned credits for prior services provided by the physicians under the terms of their participation in the Controlled Launch. For these transactions, the transaction price included noncash consideration. The services rendered by the physicians in the Controlled Launch were accounted for separately from the subsequent sales of the CellFX Systems because they were distinct from the system sales. They were distinct because they provided the Company with treatment data that could also be procured, and historically had been procured by the Company, without the corresponding system sales. This data was used by the Company to enhance marketing and promotion of its products. The Company evaluates the possible impact of variable consideration in determining the transaction price, in particular the possibility of future returns or credits. Sales agreements allow for a right of return only if the product does not no e.g The Company has made an accounting policy election to exclude from the measurement of the transaction price all taxes which are imposed on and concurrent with a specific revenue-producing transaction and collected by the entity from a customer. When there are multiple performance obligations present, the total transaction price shall be allocated to each of the performance obligations based upon the relative SSPs of those performance obligations. The Company establishes SSPs based on multiple factors including, prices charged by the Company for similar offerings, product-specific business objectives, and the estimated cost to provide the performance obligation. However, upon the sale of a new CellFX System, all performance obligations are delivered concurrently and therefore there is no not no Controlled Launch Agreements In August 2021 8

Note 10 - Segment Reporting

Note 10 - Segment Reporting	12 Months Ended
	Dec. 31, 2022
Notes to Financial Statements
Segment Reporting Disclosure [Text Block]	10. The Company operates and manages the business as one reportable and operating segment. The Company’s Chief Executive Officer acts as the chief operating decision maker ("CODM") of the Company. The CODM reviews the results of the Company on a consolidated basis, however in making certain operating decisions and assessing performance, the CODM will additionally review the disaggregated revenue results by product and geography. All of the Company’s long-lived assets are based in the United States. Revenue by product consisted of the following (in thousands): Year Ended December 31, 2022 2021 2020 Systems $ 560 $ 1,189 $ — Cycle units 140 229 — Total consolidated revenue $ 700 $ 1,418 $ — Revenue by geography consisted of the following (in thousands): Year Ended December 31, 2022 2021 2020 North America $ 517 $ 1,182 $ — Rest of World 183 236 — Total consolidated revenue $ 700 $ 1,418 $ —

Note 11 - Income Taxes

Note 11 - Income Taxes	12 Months Ended
	Dec. 31, 2022
Notes to Financial Statements
Income Tax Disclosure [Text Block]	11. Income (loss) before income taxes (in thousands): Year Ended December 31, 2022 2021 2020 Domestic $ (58,505 ) $ (63,660 ) $ (49,851 ) Foreign — — — $ (58,505 ) $ (63,660 ) $ (49,851 ) The components of the provision for income taxes are as follows (in thousands): December 31, 2022 2021 2020 Current Federal $ — $ — $ — State 3 3 3 Foreign — — — Total current 3 3 3 Deferred Federal — — — State — — — Foreign — — — Total deferred — — — Total provision for income taxes $ 3 $ 3 $ 3 State income taxes are immaterial in amount and therefore have not December 31, 2022, 2021 2020. The provision for income taxes differs from the amount estimated by applying the statutory federal income tax rate to income (loss) before taxes as follows: Year Ended December 31, 2022 2021 2020 Federal tax at statutory rate 21.0 % 21.0 % 21.0 % State tax at statutory rate 8.4 8.4 8.4 Research and development credits 0.9 1.9 2.1 Change in valuation allowance (18.4 ) (26.8 ) (43.3 ) Deferred adjustment (5.3 ) — 8.5 Change in tax rate — — 4.2 Uncertain Tax Position (5.7 ) (2.3 ) — Other (0.9 ) (2.2 ) (0.8 ) Provision for income taxes — % — % — % Deferred income taxes reflect the impact of carryforwards and temporary differences between the amounts of assets and liabilities for financial reporting purposes and such amounts as measured by tax laws. The carryforwards and temporary differences, which give rise to a significant portion of the Company’s deferred tax asset (liability) as of December 31, 2022 2021 December 31, 2022 2021 Deferred tax assets Accruals $ 3,404 $ 1,034 Net operating loss carryforwards 56,447 49,246 Tax credit carryforwards 7,111 6,611 Stock-based compensation 8,784 12,188 R&D Capitalization 3,810 — Lease liability under ASC 842 2,948 3,182 Gross deferred tax assets 82,504 72,261 Valuation allowance (79,779 ) (69,006 ) Total deferred tax assets 2,725 3,255 Deferred tax liabilities Intangibles (117 ) (365 ) ROU asset under ASC 842 (2,593 ) (2,862 ) Fixed assets (15 ) (28 ) Total deferred tax liabilities (2,725 ) (3,255 ) Net deferred tax assets/(liabilities) $ — $ — The Company’s unrecognized tax benefits as of December 31, 2022, 2021 2020 A reconciliation of the beginning and ending amounts of unrecognized tax benefit is as follows (in thousands): December 31, 2022 2021 2020 Unrecognized tax benefits at beginning of year $ 5,140 $ 2,491 $ 1,470 Increases related to current year tax positions 2,055 2,649 1,021 Increases related to prior year tax positions 1,730 — — Unrecognized tax benefits at end of year $ 8,925 $ 5,140 $ 2,491 The Company’s policy is to recognize interest and penalties related to income taxes as components of interest expense and other expense, respectively. The Company did not December 31, 2022 not twelve The Company’s valuation allowance increased by $10.8 million in the year ended December 31, 2022 December 31, 2021 As of December 31, 2022 2034. 80% As of December 31, 2022 2035 The Company is subject to taxation in the United States for Federal and for State, within various states in which the Company operates. All jurisdictions and tax years currently remain open for IRS and state taxing authorities’ examination. As of December 31, 2022 not Internal Revenue Code Section 382 one 5% 50 three may not December 31, 2022

Note 12 - Related Party Transac

Note 12 - Related Party Transactions	12 Months Ended
	Dec. 31, 2022
Notes to Financial Statements
Related Party Transactions Disclosure [Text Block]	12. On March 11, 2021, 2021 13 On June 30, 2021, 6 13 In May 2022, not May 31, 2022, one third May 31, 2023, one December 31, 2022, On September 20, 2022, 2022 13

Note 13 - Commitments and Conti

Note 13 - Commitments and Contingencies	12 Months Ended
	Dec. 31, 2022
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	13. 2021 On March 11, 2021, July 1, 2021. December 31, 2021, June 2021, 6 2022 On September 20, 2022, “2022 January 1, 2023, March 20, 2024. March 17, 2023, no September 30, 2024. December 31, 2022, 2022 Insurance Loan Agreement On May 13, 2021, February 2022, December 31, 2022, Operating Leases In January 2017, five July 2017. In May 2019, 1 1” 2,” October 2029 1 2. The Company evaluated the lease amendment under the provisions of ASC 842. not 1 November 2019) 2 May 2020) Upon commencement of each lease component, the Company reassessed and calculated the lease liability and right-of-use asset for the respective component. As a result, at the modification date, the Company remeasured its existing lease liability and recorded an additional right-of-use asset and lease liability of $2.0 million. The Company also recorded an additional right-of-use asset and lease liability of $3.0 million and $4.8 million at the commencement of Expansion Premises 1 November 2019 2 May 2020, December 31, 2022 During the years ended December 31, 2022, 2021 2020 Supplemental balance sheet information related to leases (in thousands): Year Ended December 31, Assets: 2022 2021 Right-of-use assets $ 8,062 $ 8,785 Year Ended December 31, Liabilities: 2022 2021 Current operating lease liabilities $ 896 $ 774 Non-current operating lease liabilities 9,144 10,040 Total lease liabilities $ 10,040 $ 10,814 Total cash paid for operating lease liabilities (in thousands): Year Ended December 31, 2022 2021 2020 Cash paid for operating lease liabilities $ 1,806 $ 1,643 $ 1,045 Maturities of operating lease liabilities were as follows (in thousands): Year ending December 31: 2023 $ 1,845 2024 1,910 2025 1,977 2026 2,046 2027 2,117 Thereafter 4,074 Total lease payments 13,969 Less imputed interest (3,929 ) Total lease liabilities $ 10,040 Weighted-average remaining lease term and discount rate, as of December 31, 2022, Weighted-average remaining lease term 6.83 Weighted-average discount rate 10 % Legal Proceedings From time to time, we may may In November 2022, not not March 2023, one not

Note 14 - Restructuring Charges

Note 14 - Restructuring Charges	12 Months Ended
	Dec. 31, 2022
Notes to Financial Statements
Restructuring and Related Activities Disclosure [Text Block]	14. On March 31, 2022, March 31, 2022. March 2022 December 31, 2022. December 31, 2022, On September 20, 2022, September 2022 December 31, 2022. December 31, 2022,

Note 15 - Employee Benefit Plan

Note 15 - Employee Benefit Plans	12 Months Ended
	Dec. 31, 2022
Notes to Financial Statements
Retirement Benefits [Text Block]	15. The Company sponsors a defined contribution plan under which it may not December 31, 2022, 2021 2020

Note 16 - Supplementary Financi

Note 16 - Supplementary Financial Information	12 Months Ended
	Dec. 31, 2022
Notes to Financial Statements
Quarterly Financial Information [Text Block]	16. There are no two

Significant Accounting Policies

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation Certain prior period balances have been reclassified to conform to the current period presentation in the consolidated financial statements and the accompanying notes. Sales and marketing expenses are reclassified out of general and administrative expenses, both of which are presented as separate line items. Amortization of intangible assets are reclassified to general and administrative expenses.
Consolidation, Policy [Policy Text Block]	Principles of Consolidation The accompanying consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and pursuant to the rules and regulations of the United States Securities Exchange Commission (the “SEC”). The consolidated financial statements include the financial statements of the Company and its wholly-owned subsidiaries and intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires the Company to make estimates that affect the amounts reported in the financial statements and accompanying notes to the financial statements. Estimates include, but are not
Concentration Risk, Credit Risk, Policy [Policy Text Block]	Concentration of Credit Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents and investments. The Company places its cash equivalents and investments with high credit quality financial institutions and, by policy, limits the amounts invested with any one may not
Fair Value of Financial Instruments, Policy [Policy Text Block]	Fair Value of Financial Instruments The Company believes the carrying amounts of its financial instruments, including cash equivalents, prepaid expenses and other current assets, accounts payable and accrued expenses, approximate fair value due to the short-term nature of such instruments.
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and Cash Equivalents The Company invests its cash primarily in money market funds. The Company considers all highly liquid investments purchased with an original maturity of three
Property, Plant and Equipment, Policy [Policy Text Block]	Property and Equipment Property and Equipment is recorded at cost and depreciated using the straight-line method over their estimated useful lives, ranging from three five
Inventory, Policy [Policy Text Block]	Valuation of Inventory Inventory is stated at lower of cost or net realizable value. The Company establishes the inventory basis by determining the cost based on standard costs approximating the purchase costs on a first first December 31, 2022
Goodwill and Intangible Assets, Intangible Assets, Policy [Policy Text Block]	Intangible Assets The Company’s intangible assets consist of acquired patents and licenses, which are amortized over their estimated useful lives of twelve
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]	Long-Lived Assets The Company reviews long-lived assets, consisting of property and equipment and intangible assets, for impairment during each fiscal year or when events or changes in circumstances indicate the carrying value of these assets may
Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]	Goodwill The Company records goodwill when the consideration paid in a business acquisition exceeds the fair value of the net tangible assets and the identified intangible assets acquired. The Company reviews goodwill for impairment at the reporting unit level at least annually or whenever changes in circumstances indicate that the carrying value of the goodwill may not
Revenue from Contract with Customer [Policy Text Block]	Revenue from Contracts with Customers The Company recognizes revenue at a point in time when it satisfies performance obligations by transferring control of promised goods to its customers. The amount of revenue recognized is equal to the consideration which the Company is entitled to in exchange for the promised goods, excluding any amounts assessed by government authorities for taxes which might be collected from a customer. Sales contracts often involve the sale and delivery of multiple products, each of which typically represent a separate performance obligation in the contract. While the Company sells these products on a stand-alone basis at their respective SSP, initial customer contracts will likely involve the bundling of products which will be delivered concurrently to the customer. In such instances, the full consideration of the contract will be recognized upon shipment of the products. The Company generally requires receipt of full payment prior to shipment, however, from time to time, payment terms may 9
Standard Product Warranty, Policy [Policy Text Block]	Product Warranty The Company provides a standard warranty on eligible products which provides the customer assurances that the products comply with the agreed-upon specifications. The standard warranty does not may Warranty accrual activity consisted of the following (in thousands): Year Ended December 31, 2022 2021 Beginning balance $ 80 $ — Add: Accruals for warranties issued during the period 42 80 Less: Adjustment for inventory at cost and excessive and obsolete inventory (72 ) — Ending balance $ 50 $ 80
Share-Based Payment Arrangement [Policy Text Block]	Stock-Based Compensation The Company recognizes the cost of stock-based compensation in the financial statements based upon fair value. The fair value of stock options is determined as of the grant date using the Black-Scholes option pricing model. The fair value of Restricted Stock Units (“RSU”) awards is determined based on the number of units granted and the closing price of the Company’s common stock on the grant date. The fair value of each purchase under the employee stock purchase plan (“ESPP”) is estimated at the beginning of the offering period using the Black-Scholes option pricing model. The Company’s determination of the fair value of equity-settled awards is impacted by the price of the Company’s common stock as well as changes in assumptions regarding a number of complex and subjective variables. These variables include, but are not Estimates of the fair value of equity-settled awards as of the grant date using valuation models, such as the Black-Scholes option pricing model, are affected by assumptions regarding a number of complex variables. Changes in the assumptions can materially affect the fair value of the award and the stock-based compensation expense recognized. These inputs are subjective and generally require significant analysis and judgment to develop. The Company determines the volatility factor based on its own historical volatility. The risk-free interest rate is based on the yield available on U.S. Treasury zero See Note 6
Research and Development Expense, Policy [Policy Text Block]	Research and Development Costs Research and development costs consist primarily of compensation costs, fees paid to consultants and outside service providers and organizations (including university research institutes), costs associated with clinical trials, development prototypes and other expenses relating to the acquisition, design, development and testing of the Company’s product candidates, and certain facilities related costs. Research and development costs incurred by the Company are expensed as incurred, unless the achievement of milestones, the completion of contracted work, or other information indicates that a different expensing schedule is more appropriate.
Patent Costs [Policy Text Block]	Patent Costs The Company is the owner of numerous domestic and foreign patents. Due to the significant uncertainty associated with the successful development of one not December 31, 2022, 2021 2020
Income Tax, Policy [Policy Text Block]	Income Taxes The Company accounts for income taxes under an asset and liability approach for financial accounting and reporting for income taxes. Accordingly, the Company recognizes deferred tax assets and liabilities for the expected impact of differences between the financial statements and the tax basis of assets and liabilities. The Company records a valuation allowance to reduce its deferred tax assets to the amount that is more-likely-than- not not The Company is subject to U.S. federal income taxes and state income taxes in various states. As the Company’s net operating losses have yet to be utilized, previous tax years remain open to examination by federal authorities and other jurisdictions in which the Company currently operates or has operated in the past. The Company is not The Company accounts for uncertainties in income tax law under a comprehensive model for the financial statement recognition, measurement, presentation and disclosure of uncertain tax positions taken or expected to be taken in income tax returns as prescribed by U.S. GAAP. The tax effects of a position are recognized only if it is more-likely-than- not not not no December 31, 2022 2021 not
Comprehensive Income, Policy [Policy Text Block]	Comprehensive Loss Comprehensive loss consists of net loss and unrealized gains or losses on available-for-sale investments. The Company displays comprehensive loss and its components as part of the consolidated statements of operations and comprehensive loss.
Earnings Per Share, Policy [Policy Text Block]	Net Loss per Share The Company calculates basic net loss per share by dividing net loss by the weighted average number of shares of common stock outstanding during the period. Diluted net loss per share is computed by giving effect to all potential dilutive common stock equivalents outstanding during the period. For purposes of this calculation, options to purchase common stock and common stock warrants are considered common stock equivalents. Potential common shares that have an anti-dilutive effect ( i.e. The following outstanding stock options, warrants, and RSUs to purchase common stock were excluded from the computation of diluted net loss per share for the periods presented because including them would have had an anti-dilutive effect: Year Ended December 31, 2022 2021 2020 Common stock warrants 7,303,832 — 612,310 Common stock options 5,250,696 5,996,813 5,039,194 Restricted stock units — — 111,305 Total 12,554,528 5,996,813 5,762,809
Segment Reporting, Policy [Policy Text Block]	Segment and Geographical Information The Company operates in one segment and reports segment information in accordance with ASC 280 , Segment Reporting one not December 31, 2022 2021 , See Note 10
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements In May 2014, No. 2014 09, Revenue from Contracts with Customers first 2018. 2021 9 In November 2018, No. 2018 18 Collaborative Arrangements Clarifying the Interaction between Topic 808 606 808, Collaborative Arrangements 606, Revenue from Contracts with Customers 606” 606 not January 1, 2020, not August 2021 not no In December 2019, 2019 12, Income Taxes (Topic 740 740 December 15, 2020, 740 January 1, 2021. not

Note 2 - Summary of Significa_2

Note 2 - Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2022
Notes Tables
Schedule of Product Warranty Liability [Table Text Block]	Year Ended December 31, 2022 2021 Beginning balance $ 80 $ — Add: Accruals for warranties issued during the period 42 80 Less: Adjustment for inventory at cost and excessive and obsolete inventory (72 ) — Ending balance $ 50 $ 80
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	Year Ended December 31, 2022 2021 2020 Common stock warrants 7,303,832 — 612,310 Common stock options 5,250,696 5,996,813 5,039,194 Restricted stock units — — 111,305 Total 12,554,528 5,996,813 5,762,809

Note 3 - Investments and Fair_2

Note 3 - Investments and Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2022
Notes Tables
Fair Value, Assets Measured on Recurring Basis [Table Text Block]	December 31, 2022 Assets Classification Level 1 Level 2 Level 3 Total Money market funds Cash and cash equivalents $ 57,973 $ — $ — $ 57,973 Total assets measured at fair value $ 57,973 $ — $ — $ 57,973 December 31, 2021 Assets Classification Level 1 Level 2 Level 3 Total Money market funds Cash and cash equivalents $ 23,675 $ — $ — $ 23,675 Total assets measured at fair value $ 23,675 $ — $ — $ 23,675

Note 4 - Balance Sheet Compon_2

Note 4 - Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2022
Notes Tables
Schedule of Inventory, Current [Table Text Block]	Year Ended December 31, 2022 2021 Raw materials $ — $ 2,010 Work in process — 1,371 Finished goods — 2,443 Total inventory $ — $ 5,824
Property, Plant and Equipment [Table Text Block]	December 31, 2022 2021 Leasehold improvements $ 2,519 $ 2,519 Laboratory equipment 1,118 1,019 Furniture, fixtures and equipment 966 932 Software 289 202 Construction in progress 22 186 4,914 4,858 Less: Accumulated depreciation and amortization (2,953 ) (2,396 ) $ 1,961 $ 2,462
Schedule of Finite-Lived Intangible Assets [Table Text Block]	December 31, 2022 2021 Acquired patents and licenses $ 7,985 $ 7,985 Less: Accumulated amortization (5,434 ) (4,769 ) $ 2,551 $ 3,216
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	Years ending December 31: 2023 $ 665 2024 665 2025 665 2026 556 $ 2,551
Schedule of Accrued Liabilities [Table Text Block]	December 31, 2022 2021 Compensation expense $ 1,377 $ 2,932 Controlled launch (Note 8) — 534 Director and officer liability insurance (Note 12) 571 — Clinical trial fees and costs 64 245 Professional fees 318 85 Warranty 50 80 Other 215 513 $ 2,595 $ 4,389

Note 6 - Stockholders' Equity_2

Note 6 - Stockholders' Equity and Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2022
Notes Tables
Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]	Weighted Average Weighted Remaining Number of Average Contractual Shares Exercise Price Life (in Years) Warrants outstanding at December 31, 2021 — $ — — Issued 7,317,072 2.05 Exercised (13,240 ) 2.05 Expired/Redeemed — — Warrants outstanding and exercisable at December 31, 2022 7,303,832 $ 2.05 4.43
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]	Year Ended December 31, 2022 2021 2020 Cost of revenues $ 217 $ 129 $ — Research and development 1,563 5,211 4,013 Sales and marketing 733 2,749 1,187 General and administrative 2,678 6,512 4,875 Total stock-based compensation expense $ 5,191 $ 14,601 $ 10,075
Share-Based Payment Arrangement, Cost by Plan [Table Text Block]	Year Ended December 31, 2022 2021 2020 Time-based options $ 4,467 $ 9,235 $ 8,739 Performance options 233 4,840 133 RSU — — 86 ESPP 491 526 1,117 Total stock-based compensation expense $ 5,191 $ 14,601 $ 10,075
Share-Based Payment Arrangement, Option [Member]
Notes Tables
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	Year Ended December 31, 2022 2021 2020 Expected term in years 5.3 - 6.8 5.3 - 6.1 5.3 - 6.1 Expected volatility 83 88% 78% 70% Risk-free interest rate 1.9 - 3.2% 0.9 - 1.4% 0.3 - 0.5% Dividend yield — — —
Performance Options [Member]
Notes Tables
Share-Based Payment Arrangement, Option, Activity [Table Text Block]	Stock Options Outstanding Number of shares Weighted average exercise price Weighted average remaining life (in years) Balances — December 31, 2021 1,200,097 $ 13.11 8.44 Options granted 200,000 5.32 Options exercised — — Options canceled (797,920 ) 13.32 Options expired (81,875 ) 11.28 Balances — December 31, 2022 520,302 $ 10.08 7.02 Exercisable — December 31, 2022 248,861 $ 12.25 4.92
Time-based Options [Member]
Notes Tables
Share-Based Payment Arrangement, Option, Activity [Table Text Block]	Stock Options Outstanding Number of shares Weighted average exercise price Weighted average remaining life (in years) Balances — December 31, 2021 4,796,716 $ 16.44 7.05 Options granted 1,240,100 2.59 Options exercised — — Options canceled (674,465 ) 16.73 Options expired (631,957 ) 15.05 Balances — December 31, 2022 4,730,394 $ 12.95 6.16 Exercisable — December 31, 2022 3,230,670 $ 15.39 5.07
The 2017 Employee Stock Purchase Plan [Member]
Notes Tables
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	Year Ended December 31, 2022 2021 2020 Expected term in years 0.5 - 1.0 0.5 - 1.0 0.5 - 1.0 Expected volatility 83% 78% 70 % Risk-free interest rate 0.6% - 3.5% 0.06% - 0.1% 0.1% - 1.0% Dividend yield — — —
The 2015 Plan, 2017 Plan and Inducement Plan [Member]
Notes Tables
Share-Based Payment Arrangement, Option, Activity [Table Text Block]	Stock Options Outstanding Number of shares Weighted average exercise price Weighted average remaining life (in years) Balances — December 31, 2021 5,996,813 $ 15.77 7.33 Options granted 1,440,100 2.97 Options exercised — — Options canceled (1,472,385 ) 14.88 Options expired (713,832 ) 14.62 Balances — December 31, 2022 5,250,696 $ 12.67 6.24 Exercisable — December 31, 2022 3,479,531 $ 15.17 5.06

Note 10 - Segment Reporting (Ta

Note 10 - Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2022
Notes Tables
Disaggregation of Revenue [Table Text Block]	Year Ended December 31, 2022 2021 2020 Systems $ 560 $ 1,189 $ — Cycle units 140 229 — Total consolidated revenue $ 700 $ 1,418 $ —
Revenue from External Customers by Geographic Areas [Table Text Block]	Year Ended December 31, 2022 2021 2020 North America $ 517 $ 1,182 $ — Rest of World 183 236 — Total consolidated revenue $ 700 $ 1,418 $ —

Note 11 - Income Taxes (Tables)

Note 11 - Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Notes Tables
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]	Year Ended December 31, 2022 2021 2020 Domestic $ (58,505 ) $ (63,660 ) $ (49,851 ) Foreign — — — $ (58,505 ) $ (63,660 ) $ (49,851 )
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	December 31, 2022 2021 2020 Current Federal $ — $ — $ — State 3 3 3 Foreign — — — Total current 3 3 3 Deferred Federal — — — State — — — Foreign — — — Total deferred — — — Total provision for income taxes $ 3 $ 3 $ 3
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	Year Ended December 31, 2022 2021 2020 Federal tax at statutory rate 21.0 % 21.0 % 21.0 % State tax at statutory rate 8.4 8.4 8.4 Research and development credits 0.9 1.9 2.1 Change in valuation allowance (18.4 ) (26.8 ) (43.3 ) Deferred adjustment (5.3 ) — 8.5 Change in tax rate — — 4.2 Uncertain Tax Position (5.7 ) (2.3 ) — Other (0.9 ) (2.2 ) (0.8 ) Provision for income taxes — % — % — %
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	December 31, 2022 2021 Deferred tax assets Accruals $ 3,404 $ 1,034 Net operating loss carryforwards 56,447 49,246 Tax credit carryforwards 7,111 6,611 Stock-based compensation 8,784 12,188 R&D Capitalization 3,810 — Lease liability under ASC 842 2,948 3,182 Gross deferred tax assets 82,504 72,261 Valuation allowance (79,779 ) (69,006 ) Total deferred tax assets 2,725 3,255 Deferred tax liabilities Intangibles (117 ) (365 ) ROU asset under ASC 842 (2,593 ) (2,862 ) Fixed assets (15 ) (28 ) Total deferred tax liabilities (2,725 ) (3,255 ) Net deferred tax assets/(liabilities) $ — $ —
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]	December 31, 2022 2021 2020 Unrecognized tax benefits at beginning of year $ 5,140 $ 2,491 $ 1,470 Increases related to current year tax positions 2,055 2,649 1,021 Increases related to prior year tax positions 1,730 — — Unrecognized tax benefits at end of year $ 8,925 $ 5,140 $ 2,491

Note 13 - Commitments and Con_2

Note 13 - Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2022
Notes Tables
Schedule of Information Related to Right-of-use Assets and Lease Liabilities [Table Text Block]	Year Ended December 31, Assets: 2022 2021 Right-of-use assets $ 8,062 $ 8,785 Year Ended December 31, Liabilities: 2022 2021 Current operating lease liabilities $ 896 $ 774 Non-current operating lease liabilities 9,144 10,040 Total lease liabilities $ 10,040 $ 10,814 Year Ended December 31, 2022 2021 2020 Cash paid for operating lease liabilities $ 1,806 $ 1,643 $ 1,045 Year ending December 31: 2023 $ 1,845 2024 1,910 2025 1,977 2026 2,046 2027 2,117 Thereafter 4,074 Total lease payments 13,969 Less imputed interest (3,929 ) Total lease liabilities $ 10,040 Weighted-average remaining lease term 6.83 Weighted-average discount rate 10 %

Note 2 - Summary of Significa_3

Note 2 - Summary of Significant Accounting Policies (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Finite-Lived Intangible Asset, Useful Life (Year)	12 years
Impairment, Long-Lived Asset, Held-for-Use, Total	$ 0
Goodwill, Impairment Loss	0
Liability for Uncertainty in Income Taxes, Noncurrent	$ 0	$ 0
Number of Operating Segments	1
Geographic Concentration Risk [Member] | Assets, Total [Member] | UNITED STATES
Concentration Risk, Percentage	100%	100%
General and Administrative Expense [Member]
Patent Costs	$ 500	$ 600	$ 500
Minimum [Member] | Equipment [Member]
Property, Plant and Equipment, Useful Life (Year)	3 years
Maximum [Member] | Equipment [Member]
Property, Plant and Equipment, Useful Life (Year)	5 years

Note 2 - Summary of Significa_4

Note 2 - Summary of Significant Accounting Policies - Warrant Accrual Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Beginning balance	$ 80	$ 0
Add: Accruals for warranties issued during the period	42	80
Less: Adjustment for inventory at cost and excessive and obsolete inventory	(72)	0
Ending balance	$ 50	$ 80

Note 2 - Summary of Significa_5

Note 2 - Summary of Significant Accounting Policies - Antidilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Antidilutive securities (in shares)	12,554,528	5,996,813	5,762,809
Warrant [Member]
Antidilutive securities (in shares)	7,303,832	0	612,310
Share-Based Payment Arrangement, Option [Member]
Antidilutive securities (in shares)	5,250,696	5,996,813	5,039,194
Restricted Stock Units (RSUs) [Member]
Antidilutive securities (in shares)	0	0	111,305

Note 3 - Investments and Fair_3

Note 3 - Investments and Fair Value of Financial Instruments (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Impairment of Marketable Securities	$ 0	$ 0
Fair Value, Level 1, 2 and 3 Transfers, Amount	0	0
Assets, Fair Value Disclosure, Total	57,973	23,675
Fair Value, Nonrecurring [Member]
Liabilities, Fair Value Disclosure, Total	0	0	$ 0
Assets, Fair Value Disclosure, Total	$ 0	$ 0	$ 0

Note 3 - Investments and Fair_4

Note 3 - Investments and Fair Value of Financial Instruments - Financial Assets Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Total assets measured at fair value	$ 57,973	$ 23,675
Total assets measured at fair value	(57,973)	(23,675)
Fair Value, Inputs, Level 1 [Member]
Total assets measured at fair value	57,973	23,675
Total assets measured at fair value	(57,973)	(23,675)
Fair Value, Inputs, Level 2 [Member]
Cash and Cash equivalents		0
Total assets measured at fair value	0
Total assets measured at fair value	0
Fair Value, Inputs, Level 3 [Member]
Total assets measured at fair value	0	0
Total assets measured at fair value	0	0
Money Market Funds [Member]
Cash and Cash equivalents	57,973	23,675
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and Cash equivalents	57,973	23,675
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and Cash equivalents	0	0
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and Cash equivalents	$ 0	$ 0

Note 4 - Balance Sheet Compon_3

Note 4 - Balance Sheet Components (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Depreciation, Total	$ 690	$ 480	$ 430
Finite-Lived Intangible Asset, Useful Life (Year)	12 years

Note 4 - Balance Sheet Compon_4

Note 4 - Balance Sheet Components - Inventory (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Raw materials	$ 0	$ 2,010
Work in process	0	1,371
Finished goods	0	2,443
Total inventory	$ 0	$ 5,824

Note 4 - Balance Sheet Compon_5

Note 4 - Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property and equipment, gross	$ 4,914	$ 4,858
Less: Accumulated depreciation and amortization	(2,953)	(2,396)
Property and equipment, net	1,961	2,462
Leasehold Improvements [Member]
Property and equipment, gross	2,519	2,519
Laboratory Equipment [Member]
Property and equipment, gross	1,118	1,019
Furniture and Fixtures [Member]
Property and equipment, gross	966	932
Software and Software Development Costs [Member]
Property and equipment, gross	289	202
Construction in Progress [Member]
Property and equipment, gross	$ 22	$ 186

Note 4 - Balance Sheet Compon_6

Note 4 - Balance Sheet Components - Intangible Assets, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Less: Accumulated amortization	$ (5,434)	$ (4,769)
Finite-Lived Intangible Assets, Net, Ending Balance	2,551	3,216
Acquired Patents and Licenses [Member]
Acquired patents and licenses	$ 7,985	$ 7,985

Note 4 - Balance Sheet Compon_7

Note 4 - Balance Sheet Components - Schedule of Amortization of Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
2023	$ 665
2024	665
2025	665
2026	556
Finite-Lived Intangible Assets, Net, Ending Balance	$ 2,551	$ 3,216

Note 4 - Balance Sheet Compon_8

Note 4 - Balance Sheet Components - Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Compensation expense	$ 1,377	$ 2,932
Controlled launch (Note 8)	0	534
Director and officer liability insurance (Note 12)	571	0
Clinical trial fees and costs	64	245
Professional fees	318	85
Warranty	50	80	$ 0
Other	215	513
Accrued Liabilities, Current, Total	$ 2,595	$ 4,389

Note 5 - Goodwill (Details Text

Note 5 - Goodwill (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2021 USD ($)
Goodwill, Ending Balance	$ 2,791		$ 2,791
Goodwill, Impairment Loss	$ 0
Series of Individually Immaterial Business Acquisitions [Member]
Number of Businesses Acquired		3
Business Combination, Consideration Transferred, Total		$ 5,500
Goodwill, Ending Balance		$ 2,800

Note 6 - Stockholders' Equity_3

Note 6 - Stockholders' Equity and Stock-based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Thousands							1 Months Ended								7 Months Ended	12 Months Ended
	Jun. 09, 2022	Jun. 30, 2021	Jun. 01, 2021	Feb. 05, 2021	Jan. 01, 2021	Jun. 01, 2019	Oct. 31, 2021	Jul. 31, 2021	Jun. 30, 2021	May 31, 2021	Mar. 31, 2021	Jun. 30, 2020	Dec. 31, 2017	Nov. 30, 2017	Feb. 04, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2017	Nov. 30, 2021	Dec. 31, 2016	Dec. 31, 2014
Preferred Stock, Shares Authorized (in shares)																50,000,000	50,000,000
Preferred Stock, Par or Stated Value Per Share (in dollars per share)																$ 0.001	$ 0.001
Preferred Stock, Shares Outstanding, Ending Balance (in shares)																0	0
Common Stock, Shares Authorized (in shares)																500,000,000	500,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share)																$ 0.001	$ 0.001
Proceeds from Issuance of Common Stock																$ 14,864	$ 56,697	$ 29,434
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)																$ 2.05	$ 0
Class of Warrant or Right, Exercised During Period (in shares)																13,240
Class of Warrant or Right, Outstanding (in shares)																7,303,832	0
Proceeds from Warrant Exercises																$ 26	$ 4,217	244
Share-Based Payment Arrangement, Expense																5,191	14,601	10,075
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total																$ 5,600
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)																2 years 3 months
Time-based Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value																	800	1,600
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Intrinsic Value																$ 2,300	15,100	6,700
Share-Based Payment Arrangement, Expense																$ 4,467	9,235	8,739
Time-based Options [Member] | Share-Based Payment Arrangement, Tranche One [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage																25%
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)																1 year
Performance Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Intrinsic Value																$ 800	2,500	5,500
Share-Based Payment Arrangement, Expense																233	4,840	133
Restricted Stock Units (RSUs) [Member]
Share-Based Payment Arrangement, Expense																0	0	86
Restricted Stock Units (RSUs) [Member] | Granted in 2017 [Member] | Share-Based Payment Arrangement, Employee [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)													68,800
Share-Based Payment Arrangement, Expense																0	$ 100	$ 300
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total																0
Restricted Stock Units (RSUs) [Member] | Share-Based Payment Arrangement, Tranche One [Member] | Granted in 2017 [Member] | Share-Based Payment Arrangement, Employee [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage						50%
Restricted Stock Units (RSUs) [Member] | Share-Based Payment Arrangement, Tranche Two [Member] | Granted in 2017 [Member] | Share-Based Payment Arrangement, Employee [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage			50%
Modified Performance Options [Member]
Share-Based Payment Arrangement, Expense																$ 4,100
The 2017 Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)																			10 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares)													1,500,000						1,500,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares)																1,188,657	1,022,002
Increase in Shares Available for Issuance, Threshold of Common Stock Outstanding, Number of Shares (in shares)													1,200,000						1,200,000
Increase in Shares Available for Issuance, Threshold of Common Stock Outstanding, Percent													4%						4%
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)																2,368,716
The 2017 Inducement Equity Incentive Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)														10 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares)														1,000,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares)										1,000,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)																1,053,767
The 2017 Inducement Equity Incentive Plan [Member] | Share-Based Payment Arrangement, Tranche One [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage														25%
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)														1 year
The 2017 Employee Stock Purchase Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares)													250,000						250,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares)					383,250
Increase in Shares Available for Issuance, Threshold of Common Stock Outstanding, Number of Shares (in shares)													450,000						450,000
Increase in Shares Available for Issuance, Threshold of Common Stock Outstanding, Percent													1.50%						1.50%
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)																460,999
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares)																188,097	91,378
Board of Directors Chairman [Member] | Loan Agreement [Member]
Long-Term Debt, Total		$ 0							$ 0
Board of Directors Chairman [Member] | Conversion of Loan Agreement into Common Stock [Member]
Debt Conversion, Original Debt, Amount									$ 41,000
Chief Executive Officer [Member] | Restricted Stock Units (RSUs) [Member] | Granted in 2017 [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)													160,974
Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding, Number, Ending Balance (in shares)																0
Share-Based Payment Arrangement, Expense																$ 0
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total																0
Former Director [Member] | The 2017 Plan [Member] | Share-Based Payment Arrangement, Option [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)							10 years
Share-Based Payment Arrangement, Expense																$ 1,400
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period Upon Resignation (Day)							90 days
Maximum [Member] | The 2017 Inducement Equity Incentive Plan [Member] | Share-Based Payment Arrangement, Option [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)														10 years
Rights Offering Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)	1
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)												641,571				7,317,072
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 2.05											$ 7.01				$ 2.05
Warrants and Rights Outstanding, Term (Year)	5 years											5 years				5 years
Class of Warrants or Rights, Redemption Price Per Share (in dollars per share)	$ 0.01			$ 0.01												$ 0.01		$ 0.01
Class of Warrant or Right, Period of Written Notice for Exercise (Year)	30 years											30 days				30 years
Class of Warrant or Right, Percentage Required for Redemption	200%											200%				200%
Class of Warrant or Right, Exercise, Consecutive Trading Days (Year)	20 years											10 days				20 years
Period of Time Warrants Are Not Able to Be Redeemed (Month)	3 months											6 months
Class of Warrant or Right, Exercised During Period (in shares)				5,139											636,432	13,240
Class of Warrant or Right, Outstanding (in shares)																0	7,303,832
Proceeds from Warrant Exercises															$ 4,500
Rights Offering Warrants [Member] | Maximum [Member]
Additional Proceeds That May be Received Upon Exercise of Warrants	$ 15,000
Private Placement Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)																						299,625
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)																						$ 2.67
Warrants and Rights Outstanding, Term (Year)																						7 years
Class of Warrant or Right, Exercised During Period (in shares)											45,638
Stock Issued During Period, Shares, Exercise of Warrants (in shares)											40,563
Class of Warrant or Right, Unexercised and Expired (in shares)																				600
Class of Warrant or Right, Outstanding (in shares)																0
IPO Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)																					574,985
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)																					$ 5
Warrants and Rights Outstanding, Term (Year)																					5 years
Class of Warrant or Right, Exercised During Period (in shares)											85,385
Stock Issued During Period, Shares, Exercise of Warrants (in shares)											68,958
Class of Warrant or Right, Outstanding (in shares)																0
Rights Offering [Member]
Common Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.001											$ 0.001
Equity Offering, Units, Sale of Units (in shares)	7,317,072
Shares Issued, Price Per Share (in dollars per share)	$ 2.05
Number of Shares Per Unit Issued (in shares)	1
Number of Warrants Per Unit (in shares)	1
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)	1
Stock Issued During Period, Shares, New Issues (in shares)	7,317,072
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	7,317,072
Proceeds from Issuance of Common Stock	$ 15,000
Rights Offering [Member] | Board of Directors Chairman [Member]
Investment Owned, Percent of Net Assets	56%
Private Placement [Member] | Board of Directors Chairman [Member]
Common Stock, Par or Stated Value Per Share (in dollars per share)		$ 0.001							$ 0.001
Shares Issued, Price Per Share (in dollars per share)		$ 16.40							$ 16.40
Stock Issued During Period, Shares, New Issues (in shares)		3,048,780
Proceeds from Issuance of Common Stock		$ 8,400						$ 8,400
Private Placement [Member] | Board of Directors Chairman [Member] | Conversion of Loan Agreement into Common Stock [Member]
Debt Conversion, Original Debt, Amount		$ 41,000
ATM Offering [Member]
Shares Issued, Price Per Share (in dollars per share)																	$ 27.73
Stock Issued During Period, Shares, New Issues (in shares)																	288,490
Proceeds from Issuance of Common Stock																	$ 7,400
Equity Offering, Maximum Offering Amount															$ 60,000

Note 6 - Stockholders' Equity_4

Note 6 - Stockholders' Equity and Stock-based Compensation - Summary of Warrants Activity (Details)	12 Months Ended
	Dec. 31, 2022 $ / shares shares
Warrants outstanding, number of shares (in shares) | shares	0
Warrants outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 0
Warrants issued, number of shares (in shares) | shares	7,317,072
Warrants issued, weighted average exercise price (in dollars per share) | $ / shares	$ 2.05
Warrants exercised, number of shares (in shares) | shares	(13,240)
Warrants exercised (in dollars per share) | $ / shares	$ 2.05
Warrants Expired/Redeemed, number of shares (in shares) | shares	0
Warrants Expired/Redeemed, weighted average exercise price (in dollars per share) | $ / shares	$ 0
Warrants outstanding, number of shares (in shares) | shares	7,303,832
Warrants outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 2.05
Warrants outstanding, weighted average remaining contractual life (Year)	4 years 5 months 4 days

Note 6 - Stockholders' Equity_5

Note 6 - Stockholders' Equity and Stock-based Compensation - Summary of Stock Option Activity (Details) - The 2015 Plan, 2017 Plan and Inducement Plan [Member] - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Options balances, number of shares (in shares)	5,996,813
Options balances, weighted average exercise price (in dollars per share)	$ 15.77
Options balances, weighted average remaining life (Year)	6 years 2 months 26 days	7 years 3 months 29 days
Options granted, number of shares (in shares)	1,440,100
Options granted, weighted average exercise price (in dollars per share)	$ 2.97
Options exercised, number of shares (in shares)	0
Options exercised, weighted average exercise price (in dollars per share)	$ 0
Options canceled, number of shares (in shares)	(1,472,385)
Options canceled, weighted average exercise price (in dollars per share)	$ 14.88
Options expired, number of shares (in shares)	(713,832)
Options expired, weighted average exercise price (in dollars per share)	$ 14.62
Options balances, number of shares (in shares)	5,250,696	5,996,813
Options balances, weighted average exercise price (in dollars per share)	$ 12.67	$ 15.77
Options exercisable, number of shares (in shares)	3,479,531
Options exercisable, weighted average exercise price (in dollars per share)	$ 15.17
Options exercisable, weighted average remaining life (Year)	5 years 21 days

Note 6 - Stockholders' Equity_6

Note 6 - Stockholders' Equity and Stock-based Compensation - Summary of Time-based Option Activity (Details) - Time-based Options [Member] - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Options balances, number of shares (in shares)	4,796,716
Options balances, weighted average exercise price (in dollars per share)	$ 16.44
Options balances, weighted average remaining life (Year)	6 years 1 month 28 days	7 years 18 days
Options granted, number of shares (in shares)	1,240,100
Options granted, weighted average exercise price (in dollars per share)	$ 2.59
Options exercised, number of shares (in shares)	0
Options exercised, weighted average exercise price (in dollars per share)	$ 0
Options canceled, number of shares (in shares)	(674,465)
Options canceled, weighted average exercise price (in dollars per share)	$ 16.73
Options expired, number of shares (in shares)	(631,957)
Options expired, weighted average exercise price (in dollars per share)	$ 15.05
Options balances, number of shares (in shares)	4,730,394	4,796,716
Options balances, weighted average exercise price (in dollars per share)	$ 12.95	$ 16.44
Options exercisable, number of shares (in shares)	3,230,670
Options exercisable, weighted average exercise price (in dollars per share)	$ 15.39
Options exercisable, weighted average remaining life (Year)	5 years 25 days

Note 6 - Stockholders' Equity_7

Note 6 - Stockholders' Equity and Stock-based Compensation - Summary of Performance Option Activity (Details) - Performance Options [Member] - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Options balances, number of shares (in shares)	1,200,097
Options balances, weighted average exercise price (in dollars per share)	$ 13.11
Options balances, weighted average remaining life (Year)	7 years 7 days	8 years 5 months 8 days
Options granted, number of shares (in shares)	200,000
Options granted, weighted average exercise price (in dollars per share)	$ 5.32
Options exercised, number of shares (in shares)	0
Options exercised, weighted average exercise price (in dollars per share)	$ 0
Options canceled, number of shares (in shares)	(797,920)
Options canceled, weighted average exercise price (in dollars per share)	$ 13.32
Options expired, number of shares (in shares)	(81,875)
Options expired, weighted average exercise price (in dollars per share)	$ 11.28
Options balances, number of shares (in shares)	520,302	1,200,097
Options balances, weighted average exercise price (in dollars per share)	$ 10.08	$ 13.11
Options exercisable, number of shares (in shares)	248,861
Options exercisable, weighted average exercise price (in dollars per share)	$ 12.25
Options exercisable, weighted average remaining life (Year)	4 years 11 months 1 day

Note 6 - Stockholders' Equity_8

Note 6 - Stockholders' Equity and Stock-based Compensation - Option Assumptions (Details) - Share-Based Payment Arrangement, Option [Member]	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Expected volatility		78%	70%
Dividend yield	0%	0%	0%
Minimum [Member]
Expected term in years (Year)	5 years 3 months 18 days	5 years 3 months 18 days	5 years 3 months 18 days
Risk-free interest rate	1.90%	0.90%	0.30%
Maximum [Member]
Expected term in years (Year)	6 years 9 months 18 days	6 years 1 month 6 days	6 years 1 month 6 days
Risk-free interest rate	3.20%	1.40%	0.50%

Note 6 - Stockholders' Equity_9

Note 6 - Stockholders' Equity and Stock-based Compensation - ESPP Assumptions (Details) - The 2017 Employee Stock Purchase Plan [Member]	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Expected volatility	83%	78%	70%
Dividend yield	0%	0%	0%
Minimum [Member]
Expected term in years (Year)	6 months	6 months	6 months
Risk-free interest rate	0.60%	0.06%	0.10%
Maximum [Member]
Expected term in years (Year)	1 year	1 year	1 year
Risk-free interest rate	3.50%	0.10%	1%

Note 6 - Stockholders' Equit_10

Note 6 - Stockholders' Equity and Stock-based Compensation - Stock-based Compensation Expense by Recorded Location (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Total stock-based compensation expense	$ 5,191	$ 14,601	$ 10,075
Cost of Sales [Member]
Total stock-based compensation expense	217	129	0
Research and Development Expense [Member]
Total stock-based compensation expense	1,563	5,211	4,013
Selling and Marketing Expense [Member]
Total stock-based compensation expense	733	2,749	1,187
General and Administrative Expense [Member]
Total stock-based compensation expense	$ 2,678	$ 6,512	$ 4,875

Note 6 - Stockholders' Equit_11

Note 6 - Stockholders' Equity and Stock-based Compensation - Stock-based Compensation Expense by Type (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Total stock-based compensation expense	$ 5,191	$ 14,601	$ 10,075
Time-based Options [Member]
Total stock-based compensation expense	4,467	9,235	8,739
Performance Options [Member]
Total stock-based compensation expense	233	4,840	133
Restricted Stock Units (RSUs) [Member]
Total stock-based compensation expense	0	0	86
Employee Stock Purchase Plan Award [Member]
Total stock-based compensation expense	$ 491	$ 526	$ 1,117

Note 7 - Research Grants and _2

Note 7 - Research Grants and Agreements (Details Textual) - USD ($) $ in Thousands	1 Months Ended				12 Months Ended
	May 31, 2021	Mar. 31, 2021	Sep. 30, 2019	Aug. 31, 2018	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Research and Development Expense, Total					$ 20,839	$ 28,640	$ 26,444
Old Dominion University Research Foundation [Member] | Sponsored Research Agreement SRA [Member]
Research and Development Expense, Total					$ 200	$ 300	$ 600
Old Dominion University Research Foundation [Member] | Sponsored Research Agreement SRA [Member] | Research and Development Arrangement [Member]
Long-Term Purchase Commitment, Amount	$ 300	$ 300	$ 800	$ 800

Note 8 - Controlled Launch (Det

Note 8 - Controlled Launch (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Feb. 28, 2021
Number of KOLs				70
Controlled Launch, Program Expenses	$ 100	$ 1,800
Revenue from Contract with Customer, Excluding Assessed Tax	700	1,418	$ 0
Redemption of Non Cash Credits [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 400	$ 1,100
Minimum [Member]
Number of Patients Participating in Procedure				40
Maximum [Member]
Number of Patients Participating in Procedure				50

Note 9 - Revenue (Details Textu

Note 9 - Revenue (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenue from Contract with Customer, Excluding Assessed Tax	$ 700	$ 1,418	$ 0
Redemption of Non Cash Credits [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 400	$ 1,100

Note 10 - Segment Reporting (De

Note 10 - Segment Reporting (Details Textual)	12 Months Ended
	Dec. 31, 2022
Number of Reportable Segments	1

Note 10 - Segment Reporting - R

Note 10 - Segment Reporting - Revenue by Product (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Total revenues	$ 700	$ 1,418	$ 0
System Products [Member]
Total revenues	560	1,189	0
Cycle Units Products [Member]
Total revenues	$ 140	$ 229	$ 0

Note 10 - Segment Reporting -_2

Note 10 - Segment Reporting - Revenue by Geography (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Total revenues	$ 700	$ 1,418	$ 0
North America [Member]
Total revenues	517	1,182	0
Rest of World [Member]
Total revenues	$ 183	$ 236	$ 0

Note 11 - Income Taxes (Details

Note 11 - Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Unrecognized Tax Benefits, Ending Balance	$ 8,925	$ 5,140	$ 2,491	$ 1,470
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	0
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ 10,800	$ 17,000
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2034
Domestic Tax Authority [Member]
Operating Loss Carryforwards	$ 199,900
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2035
Operating Loss Carryforwards, Not Subject to Expiration	$ 174,300
Tax Credit Carryforward, Amount	5,800
State and Local Jurisdiction [Member]
Operating Loss Carryforwards	204,600
Tax Credit Carryforward, Amount	$ 5,500

Note 11 - Income Taxes - Income

Note 11 - Income Taxes - Income (Loss) Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Domestic	$ (58,505)	$ (63,660)	$ (49,851)
Foreign	0	0	0
Loss from operations, before income taxes	$ (58,505)	$ (63,660)	$ (49,851)

Note 11 - Income Taxes - Compon

Note 11 - Income Taxes - Components of Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Current
Federal	$ 0	$ 0	$ 0
State	3	3	3
Foreign	0	0	0
Total current	3	3	3
Deferred
Federal	0	0	0
State	0	0	0
Foreign	0	0	0
Total deferred	0	0	0
Total provision for income taxes	$ 3	$ 3	$ 3

Note 11 - Income Taxes - Reconc

Note 11 - Income Taxes - Reconciliation of Provision for Income Taxes (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Federal tax at statutory rate	21%	21%	21%
State tax at statutory rate	8.40%	8.40%	8.40%
Research and development credits	0.90%	1.90%	2.10%
Change in valuation allowance	(18.40%)	(26.80%)	(43.30%)
Deferred adjustment	(5.30%)	0%	8.50%
Change in tax rate	0%	0%	4.20%
Uncertain Tax Position	(5.70%)	(2.30%)	0%
Other	(0.90%)	(2.20%)	(0.80%)
Provision for income taxes	0%	0%	0%

Note 11 - Income Taxes - Deferr

Note 11 - Income Taxes - Deferred Tax Asset (Liability) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Accruals	$ 3,404	$ 1,034
Net operating loss carryforwards	56,447	49,246
Tax credit carryforwards	7,111	6,611
Stock-based compensation	8,784	12,188
R&D Capitalization	3,810	0
Lease liability under ASC 842	2,948	3,182
Gross deferred tax assets	82,504	72,261
Valuation allowance	(79,779)	(69,006)
Total deferred tax assets	2,725	3,255
Intangibles	(117)	(365)
ROU asset under ASC 842	(2,593)	(2,862)
Fixed assets	(15)	(28)
Total deferred tax liabilities	(2,725)	(3,255)
Net deferred tax assets/(liabilities)	$ 0	$ 0

Note 11 - Income Taxes - Reco_2

Note 11 - Income Taxes - Reconciliation of Unrecognized Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Unrecognized tax benefits at beginning of year	$ 5,140	$ 2,491	$ 1,470
Increases related to current year tax positions	2,055	2,649	1,021
Increases related to prior year tax positions	1,730	0	0
Unrecognized tax benefits at beginning of year	$ 8,925	$ 5,140	$ 2,491

Note 12 - Related Party Trans_2

Note 12 - Related Party Transactions (Details Textual) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended		12 Months Ended
	Sep. 20, 2022	Jun. 30, 2021	Jul. 31, 2021	Jun. 30, 2021	May 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	May 13, 2021	May 11, 2021
Common Stock, Par or Stated Value Per Share (in dollars per share)						$ 0.001	$ 0.001
Proceeds from Issuance of Common Stock						$ 14,864	$ 56,697	$ 29,434
Board of Directors Chairman [Member] | Letter Agreement [Member]
Related Party Transaction, Amounts of Transaction						$ 600
Board of Directors Chairman [Member] | Conversion of Loan Agreement into Common Stock [Member]
Debt Conversion, Original Debt, Amount				$ 41,000
Board of Directors Chairman [Member] | Private Placement [Member]
Stock Issued During Period, Shares, New Issues (in shares)		3,048,780
Common Stock, Par or Stated Value Per Share (in dollars per share)		$ 0.001		$ 0.001
Shares Issued, Price Per Share (in dollars per share)		$ 16.40		$ 16.40
Stock Issued During Period, Value, New Issues		$ 50,000
Proceeds from Issuance of Common Stock		8,400	$ 8,400
Board of Directors Chairman [Member] | Private Placement [Member] | Conversion of Loan Agreement into Common Stock [Member]
Debt Conversion, Original Debt, Amount		41,000
Board of Directors Chairman [Member] | Loan Agreement [Member]
Debt Instrument, Face Amount									$ 41,000	$ 41,000
Long-Term Debt, Total		$ 0		$ 0
Robert W. Duggan [Member] | Letter Agreement [Member]
Directors and Officers Liability Insurance, Period (Year)						1 year
Due to Related Parties, Total						$ 1,000
Related Party Transaction, Amounts of Transaction	$ 65,000
Robert W. Duggan [Member] | Letter Agreement [Member] | Subsequent Event [Member]
Directors and Officers Liability Insurance, Period (Year)					1 year

Note 13 - Commitments and Con_3

Note 13 - Commitments and Contingencies (Details Textual) $ in Thousands

1 Months Ended

3 Months Ended

12 Months Ended

May 13, 2021 USD ($)

Jun. 30, 2021 USD ($)

May 31, 2020 USD ($)

Nov. 30, 2019 USD ($)

May 31, 2019 USD ($) a

Sep. 30, 2022 USD ($)

Dec. 31, 2022 USD ($)

Dec. 31, 2021 USD ($)

Dec. 31, 2020 USD ($)

Sep. 20, 2022 USD ($)

May 11, 2021 USD ($)

Jul. 31, 2017 a

Director and Officer Insurance Premium Payable

$ 2,600

Payment to Acquire Life Insurance Policy, Investing Activities

700

Increase (Decrease) in Operating Lease Right of Use Asset

$ (723)

$ (653)

$ (509)

Operating Lease, Right-of-Use Asset

8,062

8,785

Operating Lease, Liability, Total

10,040

10,814

Operating Lease, Expense

2,100

$ 1,900

$ 1,700

Corporate Headquarters in Hayward, California [Member]

Lessee, Operating Lease, Term of Contract (Year)

5 years

Area of Real Estate Property (Acre) | a

15,700

Increase (Decrease) in Operating Lease Right of Use Asset

$ 2,000

Operating Lease, Right-of-Use Asset

8,100

Operating Lease, Liability, Total

10,000

Corporate Headquarters in Hayward, California [Member] | Expansion Premises 1 [Member]

Area of Real Estate Property (Acre) | a

13,300

Increase (Decrease) in Operating Lease Right of Use Asset

$ 3,000

Corporate Headquarters in Hayward, California [Member] | Expansion Premises 2 [Member]

Area of Real Estate Property (Acre) | a

21,300

Increase (Decrease) in Operating Lease Right of Use Asset

$ 4,800

Board of Directors Chairman [Member] | Conversion of Loan Agreement into Common Stock [Member]

Debt Conversion, Original Debt, Amount

$ 41,000

Interest Payable

$ 600

Debt Conversion, Converted Instrument, Rate

16.40%

Loan Agreement [Member] | Board of Directors Chairman [Member]

Debt Instrument, Face Amount

41,000

$ 41,000

Debt Instrument, Interest Rate, Stated Percentage

5%

Interest Expense, Total

600

Two Thousand Twenty Two Loan Agreement [Member] | Robert W. Duggan [Member]

Debt Instrument, Face Amount

$ 65,000

Debt Instrument Quarterly Interest Rate

5

Debt Instrument, Increase, Accrued Interest

$ 900

Insurance Loan Agreement [Member]

Debt Instrument, Face Amount

$ 1,900

Debt Instrument, Interest Rate, Stated Percentage

3.69%

Interest Expense, Total

$ 1

Note 13 - Commitments and Con_4

Note 13 - Commitments and Contingencies - Information Related to Right-of-use Assets and Lease Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Right-of-use assets	$ 8,062	$ 8,785
Current operating lease liabilities	896	774
Non-current operating lease liabilities	9,144	10,040
Total lease liabilities	10,040	10,814
Cash paid for operating lease liabilities	1,806	$ 1,643	$ 1,045
2023	1,845
2024	1,910
2025	1,977
2026	2,046
2027	2,117
Thereafter	4,074
Total lease payments	13,969
Less imputed interest	$ (3,929)
Weighted-average remaining lease term (Year)	6 years 9 months 29 days
Weighted-average discount rate	10%

Note 14 - Restructuring Charg_2

Note 14 - Restructuring Charges (Details Textual) - Employee Severance [Member] - USD ($) $ in Millions	1 Months Ended
	Sep. 30, 2022	Mar. 31, 2022
March 2022 Restructuring Plan [Member]
Payments for Restructuring		$ 0.7
September 2022 Restructuring Plan [Member]
Payments for Restructuring	$ 0.2
Total Cost and Expenses [Member] | March 2022 Restructuring Plan [Member]
Restructuring Charges, Total		$ 0.7
Total Cost and Expenses [Member] | September 2022 Restructuring Plan [Member]
Restructuring Charges, Total	$ 0.2

Note 15 - Employee Benefit Pl_2

Note 15 - Employee Benefit Plans (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 0