Document And Entity Information
Document And Entity Information - USD ($) | 12 Months Ended | ||
Dec. 31, 2023 | Mar. 20, 2024 | Jun. 30, 2023 | |
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 | 2023 | ||
Document Type | 10-K | ||
Document Annual Report | true | ||
Document Period End Date | Dec. 31, 2023 | ||
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 | ||
Document Financial Statement Error Correction [Flag] | false | ||
Entity Shell Company | false | ||
Entity Public Float | $ 124,067,534 | ||
Entity Common Stock, Shares Outstanding | 55,225,333 | ||
Auditor Firm ID | 34 | ||
Auditor Name | Deloitte & Touche LLP | ||
Auditor Location | San Francisco, California |
Consolidated Balance Sheets
Consolidated Balance Sheets - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022 |
Current assets: | ||
Cash and cash equivalents | $ 44,365 | $ 61,139 |
Prepaid expenses and other current assets | 963 | 1,008 |
Total current assets | 45,328 | 62,147 |
Property and equipment, net | 1,528 | 1,961 |
Intangible assets, net | 1,886 | 2,551 |
Goodwill | 2,791 | 2,791 |
Right-of-use assets | 7,256 | 8,062 |
Other assets | 365 | 365 |
Total assets | 59,154 | 77,877 |
Current liabilities: | ||
Accounts payable | 1,836 | 1,573 |
Accrued expenses | 3,814 | 2,595 |
Lease liability, current | 1,058 | 896 |
Related party note payable, current | 0 | 917 |
Total current liabilities | 6,708 | 5,981 |
Lease liability, less current portion | 8,086 | 9,144 |
Related party note payable, less current | 0 | 65,000 |
Total liabilities | 14,794 | 80,125 |
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 – 55,144 shares and 37,235 shares at December 31, 2023 and 2022, respectively | 55 | 37 |
Additional paid-in capital | 381,220 | 292,420 |
Accumulated other comprehensive income (loss) | 0 | 0 |
Accumulated deficit | (336,915) | (294,705) |
Total stockholders’ equity (deficit) | 44,360 | (2,248) |
Total liabilities and stockholders’ equity | $ 59,154 | $ 77,877 |
Consolidated Balance Sheets (Pa
Consolidated Balance Sheets (Parentheticals) - $ / shares | Dec. 31, 2023 | Dec. 31, 2022 |
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) | 55,144,000 | 37,235,000 |
Common stock, shares outstanding (in shares) | 55,144,000 | 37,235,000 |
Consolidated Statements of Oper
Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Revenues: | ||
Total revenues | $ 0 | $ 700 |
Cost and expenses: | ||
Cost of revenues | 0 | 11,944 |
Research and development | 27,797 | 20,839 |
Sales and marketing | 0 | 12,019 |
General and administrative | 15,777 | 13,955 |
Total cost and expenses | 43,574 | 58,757 |
Loss from operations | (43,574) | (58,057) |
Other income (expense): | ||
Interest income (expense), net | 1,364 | (448) |
Total other income (expense) | 1,364 | (448) |
Loss from operations, before income taxes | (42,210) | (58,505) |
Income tax benefit | 0 | 0 |
Net loss | (42,210) | (58,505) |
Comprehensive loss | $ (42,210) | $ (58,505) |
Net loss per share: | ||
Basic and diluted net loss per share (in dollars per share) | $ (0.88) | $ (1.72) |
Weighted average shares used to compute net loss per common share — basic and diluted (in shares) | 48,038 | 33,935 |
Consolidated Statements of Stoc
Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) shares in Thousands, $ 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] | Common Stock [Member] | Additional Paid-in Capital [Member] | AOCI Attributable to Parent [Member] | Retained Earnings [Member] | Total |
Balance (in shares) at Dec. 31, 2021 | 29,716 | ||||||||||||||
Balance at Dec. 31, 2021 | $ 29 | $ 271,861 | $ 0 | $ (236,200) | $ 35,690 | ||||||||||
Issuance of shares (in shares) | 7,317 | ||||||||||||||
Issuance of shares | $ 7 | $ 14,857 | $ 0 | $ 0 | $ 14,864 | ||||||||||
Issuance of shares under employee stock purchase plan (in shares) | 188 | ||||||||||||||
Issuance of shares under employee stock purchase plan | $ 1 | 485 | 0 | 0 | 486 | ||||||||||
Issuance of shares upon exercise of warrants (in shares) | 14 | ||||||||||||||
Issuance of shares upon exercise of warrants | $ 0 | 26 | 0 | 0 | 26 | ||||||||||
Stock-based compensation expense | 0 | 5,191 | 0 | 0 | 5,191 | ||||||||||
Net loss | $ 0 | 0 | 0 | (58,505) | (58,505) | ||||||||||
Balance (in shares) at Dec. 31, 2022 | 37,235 | ||||||||||||||
Balance at Dec. 31, 2022 | $ 37 | 292,420 | 0 | (294,705) | (2,248) | ||||||||||
Issuance of shares under employee stock purchase plan (in shares) | 347 | ||||||||||||||
Issuance of shares under employee stock purchase plan | $ 1 | 394 | 0 | 0 | 395 | ||||||||||
Issuance of shares upon exercise of warrants (in shares) | 7,238 | ||||||||||||||
Issuance of shares upon exercise of warrants | $ 7 | 14,821 | 0 | 0 | 14,828 | ||||||||||
Stock-based compensation expense | 0 | 7,181 | 0 | 0 | 7,181 | ||||||||||
Net loss | $ 0 | 0 | 0 | (42,210) | (42,210) | ||||||||||
Issuance of common stock as part of debt extinguishment (in shares) | 10,023 | ||||||||||||||
Issuance of common stock as part of debt extinguishment | $ 10 | $ 65,233 | $ 0 | $ 0 | $ 65,243 | ||||||||||
Issuance of common stock upon exercise of stock options (in shares) | 301 | ||||||||||||||
Issuance of common stock upon exercise of stock options | $ 0 | 1,171 | 0 | 0 | 1,171 | ||||||||||
Balance (in shares) at Dec. 31, 2023 | 55,144 | ||||||||||||||
Balance at Dec. 31, 2023 | $ 55 | $ 381,220 | $ 0 | $ (336,915) | $ 44,360 |
Consolidated Statements of St_2
Consolidated Statements of Stockholders' Equity (Deficit) (Parentheticals) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Rights Offering [Member] | ||
Issuance cost | $ 136 | |
Private Placement [Member] | ||
Issuance cost | $ 6 | |
Shares Issued Upon Warrants Exercised [Member] | ||
Issuance cost | $ 9 |
Consolidated Statements of Cash
Consolidated Statements of Cash Flows - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Cash flows from operating activities: | ||
Net loss | $ (42,210) | $ (58,505) |
Adjustments to reconcile net loss to net cash used in operating activities: | ||
Depreciation | 542 | 690 |
Amortization of intangible assets | 665 | 665 |
Stock-based compensation | 7,181 | 5,191 |
Write-off of excessive and obsolete inventory | 0 | 8,477 |
Loss on disposal of fixed assets | 13 | 185 |
Changes in operating assets and liabilities: | ||
Accounts receivable | 0 | 61 |
Inventory | 0 | (2,653) |
Prepaid expenses and other current assets | (65) | 1,164 |
Other receivables | 109 | (41) |
Right-of-use assets | 806 | 723 |
Accounts payable | 263 | (1,304) |
Accrued expenses | 1,219 | (1,794) |
Deferred revenue | 0 | (16) |
Lease liabilities | (896) | (774) |
Accrued interest on related party note payable | (668) | 917 |
Accrued interest on note payable | 0 | 1 |
Net cash used in operating activities | (33,041) | (47,013) |
Cash flows from investing activities: | ||
Purchases of property and equipment | (121) | (401) |
Net cash used in investing activities | (121) | (401) |
Cash flows from financing activities: | ||
Proceeds from issuance of common stock under employee stock purchase plan | 395 | 486 |
Proceeds from exercises of warrants | 14,828 | 26 |
Proceeds from exercises of stock options | 1,171 | 0 |
Proceeds from issuance of common stock | 0 | 14,864 |
Proceeds from issuance of related party note | 0 | 65,000 |
Issuance cost in relation to related party note extinguishment | (6) | 0 |
Payments made on insurance loan agreement | 0 | (437) |
Net cash provided by financing activities | 16,388 | 79,939 |
Net (decrease) increase in cash and cash equivalents | (16,774) | 32,525 |
Cash and cash equivalents at beginning of period | 61,139 | 28,614 |
Cash and cash equivalents at end of period | 44,365 | 61,139 |
Supplemental disclosure of noncash investing and financing activities: | ||
Principal and accrued interest of related party note settled via issuance of common stock | (65,249) | 0 |
Equipment purchases included in accounts payable and accrued expenses | $ 0 | $ (27) |
Note 1 - Description of the Bus
Note 1 - Description of the Business | 12 Months Ended |
Dec. 31, 2023 | |
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, 2023 | |
Notes to Financial Statements | |
Significant Accounting Policies [Text Block] | 2. 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, not 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 recognized revenue at a point in time when it satisfied performance obligations by transferring control of promised goods to its customers. The amount of revenue recognized was equal to the consideration which the Company was entitled to in exchange for the promised goods, excluding any amounts assessed by government authorities for taxes which might have been collected from a customer. Sales contracts often involved the sale and delivery of multiple products, each of which typically represented a separate performance obligation in the contract. While the Company has sold these products on a stand-alone basis at their respective stand-alone selling prices (“SSP”), initial customer contracts primarily involved the bundling of products which were delivered concurrently to the customer. In such instances, the full consideration of the contract was recognized upon shipment of the products. The Company generally required receipt of full payment prior to shipment, however, from time to time, payment terms were extended to customers upon which the Company performed a necessary credit evaluation to ensure future collectability of the outstanding balance. The accounts receivable balance at December 31, 2023 zero not 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 December 31, 2023, Warranty accrual activity consisted of the following (in thousands): Year Ended December 31, 2023 2022 Beginning balance $ 50 $ 80 Add: Accruals for warranties issued during the period — 42 Less: Adjustment for inventory at cost and excessive and obsolete inventory (50 ) (72 ) Ending balance $ — $ 50 Stock-Based Compensation The Company's stock-based compensation programs include stock options and an employee stock purchase program. The Company periodically issues stock options to officers, directors, employees, and consultants for services rendered. Such issuances vest and expire according to terms established at the issuance date. Stock-based payments to officers, directors and employees, including grants of employee stock options, are recognized in the financial statements based on their grant date fair values, which are estimated using the Black-Scholes option-pricing model. Stock-based compensation expense is charged to operations on a straight-line basis over the vesting period. The Company has granted stock options with both time-based as well as performance-based vesting conditions. For stock awards with performance-based vesting conditions, the Company does not may The Company has also issued certain stock options with market-based vesting conditions. These vesting conditions relate to the achievement of certain market capitalization targets of the Company. The grant date fair value for these stock options was determined using a Monte Carlo simulation. The expense is recognized over the requisite service period for each tranche of the awards. The requisite service period is the service period derived from the Monte Carlo simulation model. If the market capitalization targets are met sooner than the derived service period, the Company will accelerate the recognition of stock-based compensation expense to reflect the cumulative expense associated with the vested shares. The Monte Carlo simulation requires the Company to make assumptions and judgements about the variables used in the calculation including the expected term, volatility of the Company's common stock, an assumed risk-free interest rate, and cost of equity. The assumptions used in the option-pricing model represent management’s best estimates. If factors change and different assumptions are used, the Company's stock-based compensation expense could be materially different in the future. 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, 2023 2022 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, 2023 2022 not Comprehensive Loss The Company displays comprehensive loss, and if applicable its components, as part of the consolidated statements of operations and comprehensive loss. There were no December 31, 2023 2022 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, 2023 2022 Common stock warrants — 7,303,832 Common stock options 9,466,036 5,250,696 Total 9,466,036 12,554,528 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, 2023 2022 , See Note 10 Recent Accounting Pronouncements Not In October 2023, 2023 06, Disclosure Improvements X not In November 2023, 2023 07, Segment Reporting 280 280 280. December 15, 2023, December 15, 2024, not In December 2023, No. 2023 09, Income Taxes 740 . December 15, 2024, |
Note 3 - Fair Value of Financia
Note 3 - Fair Value of Financial Instruments | 12 Months Ended |
Dec. 31, 2023 | |
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, not 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, 2023 Assets Classification Level 1 Level 2 Level 3 Total Money market funds Cash and cash equivalents $ 41,184 $ — $ — $ 41,184 Total assets measured at fair value $ 41,184 $ — $ — $ 41,184 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 During the years ended December 31, 2023 2022 not December 31, 2023 2022 not 1, 2 3 not December 31, 2023 2022 |
Note 4 - Balance Sheet Componen
Note 4 - Balance Sheet Components | 12 Months Ended |
Dec. 31, 2023 | |
Notes to Financial Statements | |
Supplemental Balance Sheet Disclosures [Text Block] | 4. Property and Equipment, net Property and equipment, net consisted of the following (in thousands): December 31, 2023 2022 Leasehold improvements $ 2,519 $ 2,519 Laboratory equipment 1,247 1,118 Furniture, fixtures and equipment 966 966 Software 272 289 Construction in progress — 22 5,004 4,914 Less: Accumulated depreciation and amortization (3,476 ) (2,953 ) $ 1,528 $ 1,961 Depreciation expense for the years ended December 31, 2023 2022 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, 2023 2022 Acquired patents and licenses $ 7,985 $ 7,985 Less: Accumulated amortization (6,099 ) (5,434 ) $ 1,886 $ 2,551 A schedule of the amortization of intangible assets is as follows (in thousands): Years ending December 31: 2024 $ 665 2025 665 2026 556 $ 1,886 Accrued Expenses Accrued expenses consisted of the following (in thousands): December 31, 2023 2022 Compensation expense $ 3,199 $ 1,377 Director and officer liability insurance (Note 12) — 571 Clinical trial fees and costs 84 64 Professional fees 343 318 Warranty — 50 Other 188 215 $ 3,814 $ 2,595 |
Note 5 - Goodwill
Note 5 - Goodwill | 12 Months Ended |
Dec. 31, 2023 | |
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, 2023 not |
Note 6 - Stockholders' Equity a
Note 6 - Stockholders' Equity and Stock-based Compensation | 12 Months Ended |
Dec. 31, 2023 | |
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, 2023 2022 Common Stock The Company has authorized a total of 500,000,000 shares of common stock, par value $0.001 per share. Private Placement Securities Purchase Agreement On April 30, 2023, May 9, 2023, 2022 13 Rights Offering On June 9, 2022, “2022 one one “2022 one 2022 2022 2022 May 2023, June 16, 2023, 2022 Common Stock Warrants 2022 Common Stock Warrants In connection with the 2022 2022 2022 not may not three May 10, 2023, May 9, 2023 June 16, 2023. December 31, 2023 2022 A summary of total warrants activity for the year ended December 31, 2023 Weighted Average Weighted Remaining Number of Average Contractual Shares Exercise Price Life (in Years) Warrants outstanding at December 31, 2022 7,303,832 $ 2.05 4.43 Issued — — Exercised (7,237,657 ) 2.05 Expired/Redeemed (66,175 ) 2.05 Warrants outstanding at December 31, 2023 — $ — — Equity Plans 2017 2017 The Board of Directors of the Company (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, 2023 2022, 2017 2017 2017 December 31 December 2023, 2017 December 31, 2023 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, March 2024, second December 31, 2023 A summary of stock option activity under the 2015 2017 December 31, 2023 Stock Options Outstanding Number of shares Weighted average exercise price Weighted average remaining life (in years) Balances — December 31, 2022 5,250,696 $ 12.67 6.24 Options granted 5,338,386 5.26 Options exercised (301,254 ) 3.89 Options canceled (316,494 ) 5.42 Options expired (505,298 ) 12.71 Balances — December 31, 2023 9,466,036 $ 9.01 7.78 Exercisable — December 31, 2023 3,833,663 $ 13.67 5.56 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, 2023 Stock Options Outstanding Number of shares Weighted average exercise price Weighted average remaining life (in years) Balances — December 31, 2022 4,730,394 $ 12.95 6.16 Options granted 2,390,386 4.7 Options exercised (301,254 ) 3.89 Options canceled (262,994 ) 6.06 Options expired (414,626 ) 13.01 Balances — December 31, 2023 6,141,906 $ 10.48 7.07 Exercisable — December 31, 2023 3,390,035 $ 14.47 5.28 The intrinsic value of time-based options exercised during the years ended December 31, 2023 2022 The fair value of the time-based options granted to employees and directors during the years ended December 31, 2023 2022 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 and 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, 2023 Stock Options Outstanding Number of shares Weighted average exercise price Weighted average remaining life (in years) Balances — December 31, 2022 520,302 $ 10.08 7.02 Options granted 848,000 3.13 Options exercised — — Options canceled (53,500 ) 2.31 Options expired (90,672 ) 11.35 Balances — December 31, 2023 1,224,130 $ 5.51 8.53 Exercisable — December 31, 2023 443,628 $ 7.57 7.75 The fair value of the performance options granted to employees during the years ended December 31, 2023 2022 Market-based Options Certain stock options awarded by the Company contain market conditions related to achievement of certain market capitalization targets. The options will vest and become exercisable once the specific market capitalization target is fulfilled. A summary of the market-based option activity under the 2017 December 31, 2023 Stock Options Outstanding Number of shares Weighted average exercise price Weighted average remaining life (in years) Balances — December 31, 2022 — $ — — Options granted 2,100,000 6.78 Options exercised — — Options canceled — — Options expired — — Balances — December 31, 2023 2,100,000 $ 6.78 9.44 Exercisable — December 31, 2023 — — — The fair value of the market-based options granted to employees during the year ended December 31, 2023 December 31, 2022 The Company estimates the fair value of time-based and performance-based stock options on the grant date using the Black-Scholes option pricing model. The estimated fair value of these employee stock options is amortized on a straight-line basis over the requisite service period of the awards. The Company reviews, and when deemed appropriate, updates the assumptions used on a periodic basis. The fair value of time-based and performance-based stock options was estimated using the following weighted-average assumptions: Year Ended December 31, 2023 2022 Expected term in years 5.0 - 8.0 5.3 - 6.8 Expected volatility 89 - 95% 83 - 88% Risk-free interest rate 3.7 - 4.4% 1.9 - 3.2% Dividend yield — — The Company estimates the fair value of market-based stock options on the grant date using a Monte Carlo simulation model. The estimated fair value of these employee stock options is amortized over the requisite service period for each tranche of the awards. The requisite service period is the service period derived from the Monte Carlo simulation model. If the market capitalization targets are met sooner than the derived service period, the Company will accelerate the recognition of stock-based compensation expense to reflect the cumulative expense associated with the vested shares. The fair value of market-based stock options was estimated using the following weighted-average assumptions: Year Ended December 31, 2023 2022 Expected term in years 4.0 - 6.3 — Expected volatility 90% — Risk-free interest rate 3.4% - 3.8% — Dividend yield — — 2017 The Board previously adopted and the stockholders approved the Company’s 2017 “2017 The 2017 2017 2017 December 31 2022 2023 no 2017 December 31, 2023 2022 2017 December 31, 2023 2017 The Company estimates the fair value of ESPP grants on their grant date using the Black-Scholes option pricing model. The estimated fair value of ESPP grants is amortized on a straight-line basis over the requisite service period of the grants. The Company reviews, and when deemed appropriate, updates the assumptions used on a periodic basis. The Company utilizes its estimated volatility in the Black-Scholes option pricing model to determine the fair value of ESPP grants. The fair value of ESPP grants was estimated using the following weighted-average assumptions: Year Ended December 31, 2023 2022 Expected term in years 0.5 - 1.0 0.5 - 1.0 Expected volatility 83% 83% Risk-free interest rate 5.1% - 5.5% 0.6% - 3.5% Dividend yield — — 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, 2023 2022 Cost of revenues $ — $ 217 Research and development 3,491 1,563 Sales and marketing — 733 General and administrative 3,690 2,678 Total stock-based compensation expense $ 7,181 $ 5,191 As of December 31, 2023 not Total stock-based compensation expense by award type was as follows (in thousands): Year Ended December 31, 2023 2022 Time-based options $ 3,827 $ 4,467 Performance-based options 1,977 233 Market-based options 1,130 — ESPP 247 491 Total stock-based compensation expense $ 7,181 $ 5,191 At December 31, 2023 |
Note 7 - Research Grants and Ag
Note 7 - Research Grants and Agreements | 12 Months Ended |
Dec. 31, 2023 | |
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 March 2021, May 2021 12 may December 31, 2023 2022 zero December 31, 2023 no |
Note 8 - Controlled Launch
Note 8 - Controlled Launch | 12 Months Ended |
Dec. 31, 2023 | |
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. The Company did not December 31, 2023 December 31, 2022 In September 2022, fourth 2022 During the year ended December 31, 2023 not December 31, 2022 December 31, 2022 9 |
Note 9 - Revenue
Note 9 - Revenue | 12 Months Ended |
Dec. 31, 2023 | |
Notes to Financial Statements | |
Revenue from Contract with Customer [Text Block] | 9. In connection with its Controlled Launch program in dermatology, the Company recognized revenue at a point in time when it satisfied performance obligations by transferring control of promised goods to its customers. The amount of revenue recognized was equal to the consideration which the Company was 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, not December 31, 2023 December 31, 2022 Dermatology sales contracts often involved the sale and delivery of multiple performance obligations in the contract. Performance Obligations In the Controlled Launch, systems consisted of the CellFX console and its embedded software, handpieces, and disposable tips. The console was a physical piece of hardware used by the dermatology customer to perform patient procedures. Individually the console and software were not one Handpieces were attached to the console and used in conjunction with tips to perform patient procedures. Generally, in the Controlled Launch, upon initial sale of a system to a customer, the Company included two 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, which are also still available for existing customers, 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. During part of the Controlled Launch, customers purchased CUs; when the customer’s balance of CUs on a specific system was depleted, the system would no not Shipping and handling activities are not Transaction Price In the Controlled Launch, the transaction price was the consideration to which the Company expected to be entitled to in exchange for providing the promised goods to customers. Customer orders placed for cash contemplated 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 evaluated the possible impact of variable consideration in determining the transaction price, in particular the possibility of future returns or credits. Still outstanding sales agreements allow for a right of return only if the product does not no 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, 2023 | |
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 CODM of the Company. The CODM reviews the results of the Company on a consolidated basis. In prior year, when making certain operating decisions and assessing performance, the CODM has additionally reviewed 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, 2023 2022 Systems $ — $ 560 Cycle units — 140 Total consolidated revenue $ — $ 700 Revenue by geography consisted of the following (in thousands): Year Ended December 31, 2023 2022 North America $ — $ 517 Rest of World — 183 Total consolidated revenue $ — $ 700 |
Note 11 - Income Taxes
Note 11 - Income Taxes | 12 Months Ended |
Dec. 31, 2023 | |
Notes to Financial Statements | |
Income Tax Disclosure [Text Block] | 11. Income (loss) before income taxes (in thousands): Year Ended December 31, 2023 2022 Domestic $ (42,210 ) $ (58,505 ) Foreign — — $ (42,210 ) $ (58,505 ) The components of the provision for income taxes are as follows (in thousands): December 31, 2023 2022 Current Federal $ — $ — State — 3 Foreign — — Total current — 3 Deferred Federal — — State — — Foreign — — Total deferred — — Total provision for income taxes $ — $ 3 State income taxes are immaterial in amount and therefore have not December 31, 2023 2022 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, 2023 2022 Federal tax at statutory rate 21.0 % 21.0 % State tax at statutory rate — 8.4 Research and development credits 3.7 0.9 Return to provision 2.6 — Change in valuation allowance (19.1 ) (18.4 ) Deferred adjustment (1.6 ) (5.3 ) Change in tax rate (5.8 ) — Uncertain tax position — (5.7 ) Other (0.8 ) (0.9 ) 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, 2023 2022 December 31, 2023 2022 Deferred tax assets Accruals $ 1,502 $ 3,404 Net operating loss carryforwards 61,072 56,447 Tax credit carryforwards 9,815 7,111 Stock-based compensation 7,704 8,784 R&D capitalization 7,384 3,810 Lease liability 1,920 2,948 Fixed assets 7 — Intangibles 99 — Gross deferred tax assets 89,503 82,504 Valuation allowance (87,853 ) (79,779 ) Total deferred tax assets 1,650 2,725 Deferred tax liabilities Intangibles — (117 ) Right-of-use asset (1,650 ) (2,593 ) Fixed assets — (15 ) Total deferred tax liabilities (1,650 ) (2,725 ) Net deferred tax assets/(liabilities) $ — $ — The Company’s unrecognized tax benefits as of December 31, 2023 2022 A reconciliation of the beginning and ending amounts of unrecognized tax benefit is as follows (in thousands): December 31, 2023 2022 Unrecognized tax benefits at beginning of year $ 8,925 $ 5,140 Increases related to current year tax positions 1,575 2,055 Increases related to prior year tax positions 1,129 1,730 Decreases related to prior year tax positions (1,459 ) — Unrecognized tax benefits at end of year $ 10,170 $ 8,925 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, 2023 not twelve The Company’s valuation allowance increased by $8.1 million in the year ended December 31, 2023 December 31, 2022 As of December 31, 2023 2034. 80% As of December 31, 2023 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, 2023 not Internal Revenue Code Section 382 one 5% 50 three may not December 31, 2023 |
Note 12 - Related Party Transac
Note 12 - Related Party Transactions | 12 Months Ended |
Dec. 31, 2023 | |
Notes to Financial Statements | |
Related Party Transactions Disclosure [Text Block] | 12. In May 2022, not May 31, 2022, one third May 31, 2023, one December 31, 2023 On June 9, 2022, 2022 one one 2022 $2.05 2022 On September 20, 2022, 2022 April 30, 2023, 2022 April 30, 2023. 2022 No 2022 13 |
Note 13 - Commitments and Conti
Note 13 - Commitments and Contingencies | 12 Months Ended |
Dec. 31, 2023 | |
Notes to Financial Statements | |
Commitments and Contingencies Disclosure [Text Block] | 13. 2022 On September 20, 2022, “2022 2022 January 1, 2023, March 20, 2024. March 17, 2023, 2022 no September 30, 2024. December 31, 2023 2022 April 30, 2023, 2022 April 30, 2023. May 9, 2023 2022 No 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) During the years ended December 31, 2023 2022 Supplemental balance sheet information related to leases (in thousands): Year Ended December 31, Assets: 2023 2022 Operating right-of-use assets $ 7,256 $ 8,062 Year Ended December 31, Liabilities: 2023 2022 Lease liability, current $ 1,058 $ 896 Lease liability, less current portion 8,086 9,144 Total lease liabilities $ 9,144 $ 10,040 Total cash paid for operating lease liabilities (in thousands): Year Ended December 31, 2023 2022 Cash paid for operating lease liabilities $ 1,845 $ 1,806 Maturities of operating lease liabilities were as follows (in thousands): Year ending December 31: 2024 $ 1,910 2025 1,977 2026 2,046 2027 2,117 2028 2,191 Thereafter 1,883 Total lease payments 12,124 Less imputed interest (2,980 ) Total lease liabilities $ 9,144 Weighted-average remaining lease term and discount rate, as of December 31, 2023, Weighted-average remaining lease term 5.83 Weighted-average discount rate 10 % Legal Proceedings From time to time, we may may In November 2022, not not March 2023, one not not not |
Note 14 - Restructuring Charges
Note 14 - Restructuring Charges | 12 Months Ended |
Dec. 31, 2023 | |
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, In February 2023, seven February 2023 December 31, 2023. |
Note 15 - Employee Benefit Plan
Note 15 - Employee Benefit Plans | 12 Months Ended |
Dec. 31, 2023 | |
Notes to Financial Statements | |
Retirement Benefits [Text Block] | 15. The Company sponsors a defined contribution plan under which it may not December 31, 2023 2022 |
Note 16 - Supplementary Financi
Note 16 - Supplementary Financial Information | 12 Months Ended |
Dec. 31, 2023 | |
Notes to Financial Statements | |
Quarterly Financial Information [Text Block] | 16. There are no two |
Note 17 - Subsequent Events
Note 17 - Subsequent Events | 12 Months Ended |
Dec. 31, 2023 | |
Notes to Financial Statements | |
Subsequent Events [Text Block] | 17. In March 2024, 510 In March 2024, second |
Insider Trading Arrangements
Insider Trading Arrangements | 12 Months Ended |
Dec. 31, 2023 | |
Insider Trading Arr Line Items | |
Material Terms of Trading Arrangement [Text Block] | 9B. Other Information None |
Rule 10b5-1 Arrangement Adopted [Flag] | false |
Non-Rule 10b5-1 Arrangement Adopted [Flag] | false |
Rule 10b5-1 Arrangement Terminated [Flag] | false |
Non-Rule 10b5-1 Arrangement Terminated [Flag] | false |
Significant Accounting Policies
Significant Accounting Policies (Policies) | 12 Months Ended |
Dec. 31, 2023 | |
Accounting Policies [Abstract] | |
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, not |
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 recognized revenue at a point in time when it satisfied performance obligations by transferring control of promised goods to its customers. The amount of revenue recognized was equal to the consideration which the Company was entitled to in exchange for the promised goods, excluding any amounts assessed by government authorities for taxes which might have been collected from a customer. Sales contracts often involved the sale and delivery of multiple products, each of which typically represented a separate performance obligation in the contract. While the Company has sold these products on a stand-alone basis at their respective stand-alone selling prices (“SSP”), initial customer contracts primarily involved the bundling of products which were delivered concurrently to the customer. In such instances, the full consideration of the contract was recognized upon shipment of the products. The Company generally required receipt of full payment prior to shipment, however, from time to time, payment terms were extended to customers upon which the Company performed a necessary credit evaluation to ensure future collectability of the outstanding balance. The accounts receivable balance at December 31, 2023 zero not 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 December 31, 2023, Warranty accrual activity consisted of the following (in thousands): Year Ended December 31, 2023 2022 Beginning balance $ 50 $ 80 Add: Accruals for warranties issued during the period — 42 Less: Adjustment for inventory at cost and excessive and obsolete inventory (50 ) (72 ) Ending balance $ — $ 50 |
Share-Based Payment Arrangement [Policy Text Block] | Stock-Based Compensation The Company's stock-based compensation programs include stock options and an employee stock purchase program. The Company periodically issues stock options to officers, directors, employees, and consultants for services rendered. Such issuances vest and expire according to terms established at the issuance date. Stock-based payments to officers, directors and employees, including grants of employee stock options, are recognized in the financial statements based on their grant date fair values, which are estimated using the Black-Scholes option-pricing model. Stock-based compensation expense is charged to operations on a straight-line basis over the vesting period. The Company has granted stock options with both time-based as well as performance-based vesting conditions. For stock awards with performance-based vesting conditions, the Company does not may The Company has also issued certain stock options with market-based vesting conditions. These vesting conditions relate to the achievement of certain market capitalization targets of the Company. The grant date fair value for these stock options was determined using a Monte Carlo simulation. The expense is recognized over the requisite service period for each tranche of the awards. The requisite service period is the service period derived from the Monte Carlo simulation model. If the market capitalization targets are met sooner than the derived service period, the Company will accelerate the recognition of stock-based compensation expense to reflect the cumulative expense associated with the vested shares. The Monte Carlo simulation requires the Company to make assumptions and judgements about the variables used in the calculation including the expected term, volatility of the Company's common stock, an assumed risk-free interest rate, and cost of equity. The assumptions used in the option-pricing model represent management’s best estimates. If factors change and different assumptions are used, the Company's stock-based compensation expense could be materially different in the future. 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, 2023 2022 |
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, 2023 2022 not |
Comprehensive Income, Policy [Policy Text Block] | Comprehensive Loss The Company displays comprehensive loss, and if applicable its components, as part of the consolidated statements of operations and comprehensive loss. There were no December 31, 2023 2022 |
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, 2023 2022 Common stock warrants — 7,303,832 Common stock options 9,466,036 5,250,696 Total 9,466,036 12,554,528 |
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, 2023 2022 , See Note 10 |
New Accounting Pronouncements, Policy [Policy Text Block] | Recent Accounting Pronouncements Not In October 2023, 2023 06, Disclosure Improvements X not In November 2023, 2023 07, Segment Reporting 280 280 280. December 15, 2023, December 15, 2024, not In December 2023, No. 2023 09, Income Taxes 740 . December 15, 2024, |
Note 2 - Summary of Significa_2
Note 2 - Summary of Significant Accounting Policies (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Notes Tables | |
Schedule of Product Warranty Liability [Table Text Block] | Year Ended December 31, 2023 2022 Beginning balance $ 50 $ 80 Add: Accruals for warranties issued during the period — 42 Less: Adjustment for inventory at cost and excessive and obsolete inventory (50 ) (72 ) Ending balance $ — $ 50 |
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] | Year Ended December 31, 2023 2022 Common stock warrants — 7,303,832 Common stock options 9,466,036 5,250,696 Total 9,466,036 12,554,528 |
Note 3 - Fair Value of Financ_2
Note 3 - Fair Value of Financial Instruments (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Notes Tables | |
Fair Value, Assets Measured on Recurring Basis [Table Text Block] | December 31, 2023 Assets Classification Level 1 Level 2 Level 3 Total Money market funds Cash and cash equivalents $ 41,184 $ — $ — $ 41,184 Total assets measured at fair value $ 41,184 $ — $ — $ 41,184 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 |
Note 4 - Balance Sheet Compon_2
Note 4 - Balance Sheet Components (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Notes Tables | |
Property, Plant and Equipment [Table Text Block] | December 31, 2023 2022 Leasehold improvements $ 2,519 $ 2,519 Laboratory equipment 1,247 1,118 Furniture, fixtures and equipment 966 966 Software 272 289 Construction in progress — 22 5,004 4,914 Less: Accumulated depreciation and amortization (3,476 ) (2,953 ) $ 1,528 $ 1,961 |
Schedule of Finite-Lived Intangible Assets [Table Text Block] | December 31, 2023 2022 Acquired patents and licenses $ 7,985 $ 7,985 Less: Accumulated amortization (6,099 ) (5,434 ) $ 1,886 $ 2,551 |
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] | Years ending December 31: 2024 $ 665 2025 665 2026 556 $ 1,886 |
Schedule of Accrued Liabilities [Table Text Block] | December 31, 2023 2022 Compensation expense $ 3,199 $ 1,377 Director and officer liability insurance (Note 12) — 571 Clinical trial fees and costs 84 64 Professional fees 343 318 Warranty — 50 Other 188 215 $ 3,814 $ 2,595 |
Note 6 - Stockholders' Equity_2
Note 6 - Stockholders' Equity and Stock-based Compensation (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
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, 2022 7,303,832 $ 2.05 4.43 Issued — — Exercised (7,237,657 ) 2.05 Expired/Redeemed (66,175 ) 2.05 Warrants outstanding at December 31, 2023 — $ — — |
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] | Year Ended December 31, 2023 2022 Cost of revenues $ — $ 217 Research and development 3,491 1,563 Sales and marketing — 733 General and administrative 3,690 2,678 Total stock-based compensation expense $ 7,181 $ 5,191 |
Share-Based Payment Arrangement, Cost by Plan [Table Text Block] | Year Ended December 31, 2023 2022 Time-based options $ 3,827 $ 4,467 Performance-based options 1,977 233 Market-based options 1,130 — ESPP 247 491 Total stock-based compensation expense $ 7,181 $ 5,191 |
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, 2023 2022 Expected term in years 5.0 - 8.0 5.3 - 6.8 Expected volatility 89 - 95% 83 - 88% Risk-free interest rate 3.7 - 4.4% 1.9 - 3.2% Dividend yield — — Year Ended December 31, 2023 2022 Expected term in years 4.0 - 6.3 — Expected volatility 90% — Risk-free interest rate 3.4% - 3.8% — Dividend yield — — |
Market-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, 2022 — $ — — Options granted 2,100,000 6.78 Options exercised — — Options canceled — — Options expired — — Balances — December 31, 2023 2,100,000 $ 6.78 9.44 Exercisable — December 31, 2023 — — — |
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, 2022 520,302 $ 10.08 7.02 Options granted 848,000 3.13 Options exercised — — Options canceled (53,500 ) 2.31 Options expired (90,672 ) 11.35 Balances — December 31, 2023 1,224,130 $ 5.51 8.53 Exercisable — December 31, 2023 443,628 $ 7.57 7.75 |
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, 2022 4,730,394 $ 12.95 6.16 Options granted 2,390,386 4.7 Options exercised (301,254 ) 3.89 Options canceled (262,994 ) 6.06 Options expired (414,626 ) 13.01 Balances — December 31, 2023 6,141,906 $ 10.48 7.07 Exercisable — December 31, 2023 3,390,035 $ 14.47 5.28 |
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, 2023 2022 Expected term in years 0.5 - 1.0 0.5 - 1.0 Expected volatility 83% 83% Risk-free interest rate 5.1% - 5.5% 0.6% - 3.5% 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, 2022 5,250,696 $ 12.67 6.24 Options granted 5,338,386 5.26 Options exercised (301,254 ) 3.89 Options canceled (316,494 ) 5.42 Options expired (505,298 ) 12.71 Balances — December 31, 2023 9,466,036 $ 9.01 7.78 Exercisable — December 31, 2023 3,833,663 $ 13.67 5.56 |
Note 10 - Segment Reporting (Ta
Note 10 - Segment Reporting (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Notes Tables | |
Disaggregation of Revenue [Table Text Block] | Year Ended December 31, 2023 2022 Systems $ — $ 560 Cycle units — 140 Total consolidated revenue $ — $ 700 |
Revenue from External Customers by Geographic Areas [Table Text Block] | Year Ended December 31, 2023 2022 North America $ — $ 517 Rest of World — 183 Total consolidated revenue $ — $ 700 |
Note 11 - Income Taxes (Tables)
Note 11 - Income Taxes (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Notes Tables | |
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block] | Year Ended December 31, 2023 2022 Domestic $ (42,210 ) $ (58,505 ) Foreign — — $ (42,210 ) $ (58,505 ) |
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] | December 31, 2023 2022 Current Federal $ — $ — State — 3 Foreign — — Total current — 3 Deferred Federal — — State — — Foreign — — Total deferred — — Total provision for income taxes $ — $ 3 |
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] | Year Ended December 31, 2023 2022 Federal tax at statutory rate 21.0 % 21.0 % State tax at statutory rate — 8.4 Research and development credits 3.7 0.9 Return to provision 2.6 — Change in valuation allowance (19.1 ) (18.4 ) Deferred adjustment (1.6 ) (5.3 ) Change in tax rate (5.8 ) — Uncertain tax position — (5.7 ) Other (0.8 ) (0.9 ) Provision for income taxes — % — % |
Schedule of Deferred Tax Assets and Liabilities [Table Text Block] | December 31, 2023 2022 Deferred tax assets Accruals $ 1,502 $ 3,404 Net operating loss carryforwards 61,072 56,447 Tax credit carryforwards 9,815 7,111 Stock-based compensation 7,704 8,784 R&D capitalization 7,384 3,810 Lease liability 1,920 2,948 Fixed assets 7 — Intangibles 99 — Gross deferred tax assets 89,503 82,504 Valuation allowance (87,853 ) (79,779 ) Total deferred tax assets 1,650 2,725 Deferred tax liabilities Intangibles — (117 ) Right-of-use asset (1,650 ) (2,593 ) Fixed assets — (15 ) Total deferred tax liabilities (1,650 ) (2,725 ) Net deferred tax assets/(liabilities) $ — $ — |
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block] | December 31, 2023 2022 Unrecognized tax benefits at beginning of year $ 8,925 $ 5,140 Increases related to current year tax positions 1,575 2,055 Increases related to prior year tax positions 1,129 1,730 Decreases related to prior year tax positions (1,459 ) — Unrecognized tax benefits at end of year $ 10,170 $ 8,925 |
Note 13 - Commitments and Con_2
Note 13 - Commitments and Contingencies (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Notes Tables | |
Schedule of Information Related to Right-of-use Assets and Lease Liabilities [Table Text Block] | Year Ended December 31, Assets: 2023 2022 Operating right-of-use assets $ 7,256 $ 8,062 Year Ended December 31, Liabilities: 2023 2022 Lease liability, current $ 1,058 $ 896 Lease liability, less current portion 8,086 9,144 Total lease liabilities $ 9,144 $ 10,040 Year Ended December 31, 2023 2022 Cash paid for operating lease liabilities $ 1,845 $ 1,806 Year ending December 31: 2024 $ 1,910 2025 1,977 2026 2,046 2027 2,117 2028 2,191 Thereafter 1,883 Total lease payments 12,124 Less imputed interest (2,980 ) Total lease liabilities $ 9,144 Weighted-average remaining lease term 5.83 Weighted-average discount rate 10 % |
Note 2 - Summary of Significa_3
Note 2 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
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 | $ 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, 2023 | Dec. 31, 2022 | |
Beginning balance | $ 50 | $ 80 |
Add: Accruals for warranties issued during the period | 0 | 42 |
Less: Adjustment for inventory at cost and excessive and obsolete inventory | (50) | (72) |
Ending balance | $ 0 | $ 50 |
Note 2 - Summary of Significa_5
Note 2 - Summary of Significant Accounting Policies - Antidilutive Securities (Details) - shares | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Antidilutive securities (in shares) | 9,466,036 | 12,554,528 |
Warrant [Member] | ||
Antidilutive securities (in shares) | 0 | 7,303,832 |
Share-Based Payment Arrangement, Option [Member] | ||
Antidilutive securities (in shares) | 9,466,036 | 5,250,696 |
Note 3 - Fair Value of Financ_3
Note 3 - Fair Value of Financial Instruments (Details Textual) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Impairment of Marketable Securities | $ 0 | $ 0 |
Fair Value, Level 1, 2 and 3 Transfers, Amount | 0 | 0 |
Assets, Fair Value Disclosure | 41,184 | 57,973 |
Fair Value, Recurring [Member] | ||
Liabilities, Fair Value Disclosure | 0 | 0 |
Assets, Fair Value Disclosure | $ 0 | $ 0 |
Note 3 - Investments and Fair V
Note 3 - Investments and Fair Value of Financial Instruments - Financial Assets Measured on a Recurring Basis (Details) - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022 |
Total assets measured at fair value | $ 41,184 | $ 57,973 |
Total assets measured at fair value | (41,184) | (57,973) |
Fair Value, Inputs, Level 1 [Member] | ||
Total assets measured at fair value | 41,184 | 57,973 |
Total assets measured at fair value | (41,184) | (57,973) |
Fair Value, Inputs, Level 2 [Member] | ||
Total assets measured at fair value | 0 | 0 |
Total assets measured at fair value | 0 | 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 | 41,184 | 57,973 |
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member] | ||
Cash and Cash equivalents | 41,184 | 57,973 |
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, 2023 | Dec. 31, 2022 | |
Depreciation | $ 542 | $ 690 |
Finite-Lived Intangible Asset, Useful Life (Year) | 12 years |
Note 4 - Balance Sheet Compon_4
Note 4 - Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022 |
Property and equipment, gross | $ 5,004 | $ 4,914 |
Less: Accumulated depreciation and amortization | (3,476) | (2,953) |
Property and equipment, net | 1,528 | 1,961 |
Leasehold Improvements [Member] | ||
Property and equipment, gross | 2,519 | 2,519 |
Laboratory Equipment [Member] | ||
Property and equipment, gross | 1,247 | 1,118 |
Furniture and Fixtures [Member] | ||
Property and equipment, gross | 966 | 966 |
Software and Software Development Costs [Member] | ||
Property and equipment, gross | 272 | 289 |
Construction in Progress [Member] | ||
Property and equipment, gross | $ 0 | $ 22 |
Note 4 - Balance Sheet Compon_5
Note 4 - Balance Sheet Components - Intangible Assets, Net (Details) - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022 |
Less: Accumulated amortization | $ (6,099) | $ (5,434) |
Finite-Lived Intangible Assets, Net | 1,886 | 2,551 |
Acquired Patents and Licenses [Member] | ||
Acquired patents and licenses | $ 7,985 | $ 7,985 |
Note 4 - Balance Sheet Compon_6
Note 4 - Balance Sheet Components - Schedule of Amortization of Intangible Assets (Details) - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022 |
2024 | $ 665 | |
2025 | 665 | |
2026 | 556 | |
Finite-Lived Intangible Assets, Net | $ 1,886 | $ 2,551 |
Note 4 - Balance Sheet Compon_7
Note 4 - Balance Sheet Components - Accrued Expenses (Details) - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 |
Compensation expense | $ 3,199 | $ 1,377 | |
Director and officer liability insurance (Note 12) | 0 | 571 | |
Clinical trial fees and costs | 84 | 64 | |
Professional fees | 343 | 318 | |
Warranty | 0 | 50 | $ 80 |
Other | 188 | 215 | |
Accrued Liabilities, Current | $ 3,814 | $ 2,595 |
Note 5 - Goodwill (Details Text
Note 5 - Goodwill (Details Textual) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2023 USD ($) | Dec. 31, 2014 USD ($) | Dec. 31, 2022 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 | 6 Months Ended | 12 Months Ended | ||||||||
Apr. 30, 2023 | Jan. 01, 2023 | Jun. 09, 2022 | Mar. 31, 2024 | Dec. 31, 2023 | May 31, 2021 | Nov. 30, 2017 | Jun. 15, 2023 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2017 | |
Preferred Stock, Shares Authorized (in shares) | 50,000,000 | 50,000,000 | 50,000,000 | ||||||||
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ 0.001 | $ 0.001 | $ 0.001 | ||||||||
Preferred Stock, Shares Outstanding, Ending Balance (in shares) | 0 | 0 | 0 | ||||||||
Common Stock, Shares Authorized (in shares) | 500,000,000 | 500,000,000 | 500,000,000 | ||||||||
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ 0.001 | $ 0.001 | $ 0.001 | ||||||||
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ 0 | $ 0 | $ 2.05 | ||||||||
Proceeds from Issuance of Common Stock | $ 0 | $ 14,864 | |||||||||
Class of Warrant or Right, Exercised During Period (in shares) | 7,237,657 | ||||||||||
Proceeds from Warrant Exercises | $ 14,828 | $ 26 | |||||||||
Class of Warrant or Right, Outstanding (in shares) | 0 | 0 | 7,303,832 | ||||||||
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $ 9,700 | $ 9,700 | |||||||||
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year) | 4 years 2 months 8 days | ||||||||||
Time-based Options [Member] | |||||||||||
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value | $ 900 | ||||||||||
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Intrinsic Value | $ 9,000 | $ 2,300 | |||||||||
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 | $ 2,000 | 800 | |||||||||
Market-based Options [Member] | |||||||||||
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Intrinsic Value | $ 10,500 | $ 0 | |||||||||
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 | ||||||||||
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares) | 1,200,000 | 1,375,000 | 1,188,657 | ||||||||
Increase in Shares Available for Issuance, Threshold of Common Stock Outstanding, Number of Shares (in shares) | 1,200,000 | ||||||||||
Increase in Shares Available for Issuance, Threshold of Common Stock Outstanding, Percent | 4% | ||||||||||
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares) | 231,763 | 231,763 | |||||||||
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) | 1,249,126 | 1,249,126 | |||||||||
The 2017 Inducement Equity Incentive Plan [Member] | Subsequent Event [Member] | |||||||||||
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares) | 2,000,000 | ||||||||||
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 Inducement Equity Incentive Plan [Member] | Share-Based Payment Arrangement, Option [Member] | Maximum [Member] | |||||||||||
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year) | 10 years | ||||||||||
The 2017 Employee Stock Purchase Plan [Member] | |||||||||||
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares) | 250,000 | ||||||||||
Increase in Shares Available for Issuance, Threshold of Common Stock Outstanding, Number of Shares (in shares) | 450,000 | ||||||||||
Increase in Shares Available for Issuance, Threshold of Common Stock Outstanding, Percent | 1.50% | ||||||||||
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares) | 113,318 | 113,318 | |||||||||
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares) | 347,681 | 188,097 | |||||||||
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, Exercise Price of Warrants or Rights (in dollars per share) | $ 2.05 | $ 2.05 | $ 2.05 | ||||||||
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | 7,317,072 | 7,317,072 | |||||||||
Class of Warrants or Rights, Redemption Price Per Share (in dollars per share) | $ 0.01 | $ 0.01 | |||||||||
Class of Warrant or Right, Period of Written Notice for Exercise (Day) | 30 days | ||||||||||
Class of Warrant or Right, Percentage Required for Redemption | 200% | 200% | |||||||||
Class of Warrant or Right, Exercise, Consecutive Trading Days (Day) | 20 days | ||||||||||
Class of Warrant or Right, Exercised During Period (in shares) | 7,250,897 | 66,175 | |||||||||
Proceeds from Warrant Exercises | $ 14,900 | ||||||||||
Class of Warrant or Right, Outstanding (in shares) | 0 | 0 | |||||||||
Loan Agreement [Member] | |||||||||||
Debt Instrument, Decrease, Forgiveness | $ 65,000 | ||||||||||
Private Placement [Member] | Robert W. Duggan [Member] | |||||||||||
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ 0.001 | ||||||||||
Stock Issued During Period, Shares, New Issues (in shares) | 10,022,937 | ||||||||||
Shares Issued, Price Per Share (in dollars per share) | $ 6.51 | ||||||||||
Rights Offering [Member] | |||||||||||
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ 0.001 | ||||||||||
Stock Issued During Period, Shares, New Issues (in shares) | 7,317,072 | ||||||||||
Shares Issued, Price Per Share (in dollars per share) | $ 2.05 | ||||||||||
Equity Offering, Units, Sale of Units (in shares) | 7,317,072 | ||||||||||
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 Warrants or Rights (in shares) | 7,317,072 | ||||||||||
Proceeds from Issuance of Common Stock | $ 15,000 | ||||||||||
Class of Warrants or Rights, Redemption Price Per Share (in dollars per share) | $ 0.01 | ||||||||||
Rights Offering [Member] | Board of Directors Chairman [Member] | |||||||||||
Investment Owned, Percent of Net Assets | 56% | ||||||||||
Rights Offering [Member] | Robert W. Duggan [Member] | |||||||||||
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ 0.001 | ||||||||||
Shares Issued, Price Per Share (in dollars per share) | $ 2.05 | ||||||||||
Equity Offering, Units, Sale of Units (in shares) | 7,317,072 | ||||||||||
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 | ||||||||||
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ 2.05 | ||||||||||
Investment Owned, Percent of Net Assets | 56% |
Note 6 - Stockholders' Equity_4
Note 6 - Stockholders' Equity and Stock-based Compensation - Summary of Warrants Activity (Details) | 12 Months Ended |
Dec. 31, 2023 $ / shares shares | |
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 |
Warrants issued, number of shares (in shares) | shares | 0 |
Warrants issued, weighted average exercise price (in dollars per share) | $ / shares | $ 0 |
Warrants exercised, number of shares (in shares) | shares | (7,237,657) |
Warrants exercised (in dollars per share) | $ / shares | $ 2.05 |
Warrants Expired/Redeemed, number of shares (in shares) | shares | (66,175) |
Warrants Expired/Redeemed, weighted average exercise price (in dollars per share) | $ / shares | $ 2.05 |
Warrants outstanding, number of shares (in shares) | shares | 0 |
Warrants outstanding, weighted average exercise price (in dollars per share) | $ / shares | $ 0 |
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, 2023 | Dec. 31, 2022 | |
Options balances, number of shares (in shares) | 5,250,696 | |
Options balances, weighted average exercise price (in dollars per share) | $ 12.67 | |
Options balances, weighted average remaining life (Year) | 7 years 9 months 10 days | 6 years 2 months 26 days |
Options granted, number of shares (in shares) | 5,338,386 | |
Options granted, weighted average exercise price (in dollars per share) | $ 5.26 | |
Options exercised, number of shares (in shares) | (301,254) | |
Options exercised, weighted average exercise price (in dollars per share) | $ 3.89 | |
Options canceled, number of shares (in shares) | (316,494) | |
Options canceled, weighted average exercise price (in dollars per share) | $ 5.42 | |
Options expired, number of shares (in shares) | (505,298) | |
Options expired, weighted average exercise price (in dollars per share) | $ 12.71 | |
Options balances, number of shares (in shares) | 9,466,036 | 5,250,696 |
Options balances, weighted average exercise price (in dollars per share) | $ 9.01 | $ 12.67 |
Options exercisable, number of shares (in shares) | 3,833,663 | |
Options exercisable, weighted average exercise price (in dollars per share) | $ 13.67 | |
Options exercisable, weighted average remaining life (Year) | 5 years 6 months 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, 2023 | Dec. 31, 2022 | |
Options balances, number of shares (in shares) | 4,730,394 | |
Options balances, weighted average exercise price (in dollars per share) | $ 12.95 | |
Options balances, weighted average remaining life (Year) | 7 years 25 days | 6 years 1 month 28 days |
Options granted, number of shares (in shares) | 2,390,386 | |
Options granted, weighted average exercise price (in dollars per share) | $ 4.7 | |
Options exercised, number of shares (in shares) | (301,254) | |
Options exercised, weighted average exercise price (in dollars per share) | $ 3.89 | |
Options canceled, number of shares (in shares) | (262,994) | |
Options canceled, weighted average exercise price (in dollars per share) | $ 6.06 | |
Options expired, number of shares (in shares) | (414,626) | |
Options expired, weighted average exercise price (in dollars per share) | $ 13.01 | |
Options balances, number of shares (in shares) | 6,141,906 | 4,730,394 |
Options balances, weighted average exercise price (in dollars per share) | $ 10.48 | $ 12.95 |
Options exercisable, number of shares (in shares) | 3,390,035 | |
Options exercisable, weighted average exercise price (in dollars per share) | $ 14.47 | |
Options exercisable, weighted average remaining life (Year) | 5 years 3 months 10 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, 2023 | Dec. 31, 2022 | |
Options balances, number of shares (in shares) | 520,302 | |
Options balances, weighted average exercise price (in dollars per share) | $ 10.08 | |
Options balances, weighted average remaining life (Year) | 8 years 6 months 10 days | 7 years 7 days |
Options granted, number of shares (in shares) | 848,000 | |
Options granted, weighted average exercise price (in dollars per share) | $ 3.13 | |
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) | (53,500) | |
Options canceled, weighted average exercise price (in dollars per share) | $ 2.31 | |
Options expired, number of shares (in shares) | (90,672) | |
Options expired, weighted average exercise price (in dollars per share) | $ 11.35 | |
Options balances, number of shares (in shares) | 1,224,130 | 520,302 |
Options balances, weighted average exercise price (in dollars per share) | $ 5.51 | $ 10.08 |
Options exercisable, number of shares (in shares) | 443,628 | |
Options exercisable, weighted average exercise price (in dollars per share) | $ 7.57 | |
Options exercisable, weighted average remaining life (Year) | 7 years 9 months |
Note 6 - Stockholders' Equity_8
Note 6 - Stockholders' Equity and Stock-based Compensation - Summary of Market-based Option Activity (Details) - Market-based Options [Member] | 12 Months Ended |
Dec. 31, 2023 $ / shares shares | |
Options balances, number of shares (in shares) | shares | 0 |
Options balances, weighted average exercise price (in dollars per share) | $ / shares | $ 0 |
Options granted, number of shares (in shares) | shares | 2,100,000 |
Options granted, weighted average exercise price (in dollars per share) | $ / shares | $ 6.78 |
Options exercised, number of shares (in shares) | shares | 0 |
Options exercised, weighted average exercise price (in dollars per share) | $ / shares | $ 0 |
Options canceled, number of shares (in shares) | shares | 0 |
Options canceled, weighted average exercise price (in dollars per share) | $ / shares | $ 0 |
Options expired, number of shares (in shares) | shares | 0 |
Options expired, weighted average exercise price (in dollars per share) | $ / shares | $ 0 |
Options balances, number of shares (in shares) | shares | 2,100,000 |
Options balances, weighted average exercise price (in dollars per share) | $ / shares | $ 6.78 |
Options balances, weighted average remaining life (Year) | 9 years 5 months 8 days |
Options exercisable, number of shares (in shares) | shares | 0 |
Options exercisable, weighted average exercise price (in dollars per share) | $ / shares | $ 0 |
Note 6 - Stockholders' Equity_9
Note 6 - Stockholders' Equity and Stock-based Compensation - Option Assumptions (Details) | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Market-based Options [Member] | ||
Expected volatility | 90% | 0% |
Risk-free interest rate | 0% | |
Dividend yield | 0% | 0% |
Time-based and Performance Options [Member] | ||
Dividend yield | 0% | |
Minimum [Member] | Market-based Options [Member] | ||
Expected term in years (Year) | 4 years | |
Risk-free interest rate | 3.40% | |
Minimum [Member] | Time-based and Performance Options [Member] | ||
Expected term in years (Year) | 5 years | 5 years 3 months 18 days |
Expected volatility | 89% | 83% |
Risk-free interest rate | 3.70% | 1.90% |
Maximum [Member] | Market-based Options [Member] | ||
Expected term in years (Year) | 6 years 3 months 18 days | |
Risk-free interest rate | 3.80% | |
Maximum [Member] | Time-based and Performance Options [Member] | ||
Expected term in years (Year) | 8 years | 6 years 9 months 18 days |
Expected volatility | 95% | 88% |
Risk-free interest rate | 4.40% | 3.20% |
Note 6 - Stockholders' Equit_10
Note 6 - Stockholders' Equity and Stock-based Compensation - ESPP Assumptions (Details) - The 2017 Employee Stock Purchase Plan [Member] | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Expected volatility | 83% | 83% |
Dividend yield | 0% | 0% |
Minimum [Member] | ||
Expected term in years (Year) | 6 months | 6 months |
Risk-free interest rate | 5.10% | 0.60% |
Maximum [Member] | ||
Expected term in years (Year) | 1 year | 1 year |
Risk-free interest rate | 5.50% | 3.50% |
Note 6 - Stockholders' Equit_11
Note 6 - Stockholders' Equity and Stock-based Compensation - Stock-based Compensation Expense by Recorded Location (Details) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Total stock-based compensation expense | $ 7,181 | $ 5,191 |
Cost of Sales [Member] | ||
Total stock-based compensation expense | 0 | 217 |
Research and Development Expense [Member] | ||
Total stock-based compensation expense | 3,491 | 1,563 |
Selling and Marketing Expense [Member] | ||
Total stock-based compensation expense | 0 | 733 |
General and Administrative Expense [Member] | ||
Total stock-based compensation expense | $ 3,690 | $ 2,678 |
Note 6 - Stockholders' Equit_12
Note 6 - Stockholders' Equity and Stock-based Compensation - Stock-based Compensation Expense by Type (Details) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Total stock-based compensation expense | $ 7,181 | $ 5,191 |
Time-based Options [Member] | ||
Total stock-based compensation expense | 3,827 | 4,467 |
Performance-based Options [Member] | ||
Total stock-based compensation expense | 1,977 | 233 |
Market-based Options [Member] | ||
Total stock-based compensation expense | 1,130 | 0 |
Employee Stock Purchase Plan Award [Member] | ||
Total stock-based compensation expense | $ 247 | $ 491 |
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 | Dec. 31, 2023 | Dec. 31, 2022 | |
Research and Development Expense | $ 27,797 | $ 20,839 | ||
Old Dominion University Research Foundation [Member] | Sponsored Research Agreement SRA [Member] | ||||
Research and Development Expense | $ 0 | $ 200 | ||
Old Dominion University Research Foundation [Member] | Sponsored Research Agreement SRA [Member] | Research and Development Arrangement [Member] | ||||
Long-Term Purchase Commitment, Amount | $ 300 | $ 300 |
Note 8 - Controlled Launch (Det
Note 8 - Controlled Launch (Details Textual) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) | Feb. 28, 2021 | |
Number of KOLs | 70 | ||
Controlled Launch, Program Expenses | $ 0 | $ 600 | |
Revenue from Contract with Customer, Excluding Assessed Tax | 0 | 700 | |
CellFX System [Member] | |||
Contract with Customer, Receivable, Credit Loss Expense (Reversal) | (500) | ||
Controlled Launch [Member] | |||
Revenue from Contract with Customer, Excluding Assessed Tax | 100 | ||
Redemption of Non Cash Credits [Member] | |||
Revenue from Contract with Customer, Excluding Assessed Tax | $ 0 | $ 400 | |
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, 2023 | Dec. 31, 2022 | |
Revenue from Contract with Customer, Excluding Assessed Tax | $ 0 | $ 700 |
Redemption of Non Cash Credits [Member] | ||
Revenue from Contract with Customer, Excluding Assessed Tax | $ 0 | $ 400 |
Note 10 - Segment Reporting (De
Note 10 - Segment Reporting (Details Textual) | 12 Months Ended |
Dec. 31, 2023 | |
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, 2023 | Dec. 31, 2022 | |
Total revenues | $ 0 | $ 700 |
System Products [Member] | ||
Total revenues | 0 | 560 |
Cycle Units Products [Member] | ||
Total revenues | $ 0 | $ 140 |
Note 10 - Segment Reporting -_2
Note 10 - Segment Reporting - Revenue by Geography (Details) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Total revenues | $ 0 | $ 700 |
North America [Member] | ||
Total revenues | 0 | 517 |
Rest of World [Member] | ||
Total revenues | $ 0 | $ 183 |
Note 11 - Income Taxes (Details
Note 11 - Income Taxes (Details Textual) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | |
Unrecognized Tax Benefits | $ 10,170 | $ 8,925 | $ 5,140 |
Unrecognized Tax Benefits that Would Impact Effective Tax Rate | 0 | ||
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount | 8,100 | $ 10,800 | |
Domestic Tax Authority [Member] | |||
Operating Loss Carryforwards | 222,000 | ||
Operating Loss Carryforwards, Not Subject to Expiration | 196,400 | ||
Tax Credit Carryforward, Amount | 8,600 | ||
State and Local Jurisdiction [Member] | |||
Operating Loss Carryforwards | 204,400 | ||
Tax Credit Carryforward, Amount | $ 8,100 |
Note 11 - Income Taxes - Income
Note 11 - Income Taxes - Income (Loss) Before Income Taxes (Details) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Domestic | $ (42,210) | $ (58,505) |
Foreign | 0 | 0 |
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest | $ (42,210) | $ (58,505) |
Note 11 - Income Taxes - Compon
Note 11 - Income Taxes - Components of Provision for Income Taxes (Details) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Current | ||
Federal | $ 0 | $ 0 |
State | 0 | 3 |
Foreign | 0 | 0 |
Total current | 0 | 3 |
Deferred | ||
Federal | 0 | 0 |
State | 0 | 0 |
Foreign | 0 | 0 |
Total deferred | 0 | 0 |
Total provision for income taxes | $ 0 | $ 3 |
Note 11 - Income Taxes - Reconc
Note 11 - Income Taxes - Reconciliation of Provision for Income Taxes (Details) | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Federal tax at statutory rate | 21% | 21% |
State tax at statutory rate | 0% | 8.40% |
Research and development credits | 3.70% | 0.90% |
Return to provision | 2.60% | 0% |
Change in valuation allowance | (19.10%) | (18.40%) |
Deferred adjustment | (1.60%) | (5.30%) |
Change in tax rate | (5.80%) | 0% |
Uncertain tax position | 0% | (5.70%) |
Other | (0.80%) | (0.90%) |
Provision for income taxes | 0% | 0% |
Note 11 - Income Taxes - Deferr
Note 11 - Income Taxes - Deferred Tax Asset (Liability) (Details) - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022 |
Accruals | $ 1,502 | $ 3,404 |
Net operating loss carryforwards | 61,072 | 56,447 |
Tax credit carryforwards | 9,815 | 7,111 |
Stock-based compensation | 7,704 | 8,784 |
R&D capitalization | 7,384 | 3,810 |
Lease liability | 1,920 | 2,948 |
Fixed assets | (7) | 0 |
Intangibles | (99) | 0 |
Gross deferred tax assets | 89,503 | 82,504 |
Valuation allowance | (87,853) | (79,779) |
Total deferred tax assets | 1,650 | 2,725 |
Intangibles | 0 | (117) |
Right-of-use asset | (1,650) | (2,593) |
Fixed assets | 0 | (15) |
Total deferred tax liabilities | (1,650) | (2,725) |
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, 2023 | Dec. 31, 2022 | |
Unrecognized tax benefits at beginning of year | $ 8,925 | $ 5,140 |
Increases related to current year tax positions | 1,575 | 2,055 |
Increases related to prior year tax positions | 1,129 | 1,730 |
Decreases related to prior year tax positions | (1,459) | 0 |
Unrecognized tax benefits at beginning of year | $ 10,170 | $ 8,925 |
Note 12 - Related Party Trans_2
Note 12 - Related Party Transactions (Details Textual) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | |||||||
May 31, 2023 | Apr. 30, 2023 | Sep. 20, 2022 | Jun. 09, 2022 | Mar. 31, 2023 | Dec. 31, 2023 | Sep. 30, 2023 | Dec. 31, 2022 | |
Accrued Liabilities, Current | $ 3,814 | $ 2,595 | ||||||
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ 0.001 | $ 0.001 | ||||||
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ 0 | $ 2.05 | ||||||
Loan Agreement [Member] | ||||||||
Debt Instrument, Decrease, Forgiveness | $ 65,000 | |||||||
Interest Payable | $ 200 | |||||||
Rights Offering [Member] | ||||||||
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 | |||||||
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ 0.001 | |||||||
Number of Warrants Per Unit (in shares) | 1 | |||||||
Stock Issued During Period, Shares, New Issues (in shares) | 7,317,072 | |||||||
Robert W. Duggan [Member] | Rights Offering [Member] | ||||||||
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 | |||||||
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ 0.001 | |||||||
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 | |||||||
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ 2.05 | |||||||
Investment Owned, Percent of Net Assets | 56% | |||||||
Robert W. Duggan [Member] | Private Placement [Member] | ||||||||
Shares Issued, Price Per Share (in dollars per share) | $ 6.51 | |||||||
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ 0.001 | |||||||
Stock Issued During Period, Shares, New Issues (in shares) | 10,022,937 | |||||||
Letter Agreement [Member] | Robert W. Duggan [Member] | ||||||||
Directors and Officers Liability Insurance, Period (Year) | 1 year | |||||||
Related Party Transaction, Amounts of Transaction | $ 1,000 | $ 65,000 | ||||||
Accrued Liabilities, Current | $ 0 |
Note 13 - Commitments and Con_3
Note 13 - Commitments and Contingencies (Details Textual) $ / shares in Units, $ in Millions | 12 Months Ended | |||||
Apr. 30, 2023 USD ($) $ / shares shares | Dec. 31, 2023 USD ($) $ / shares | Dec. 31, 2022 USD ($) $ / shares | Sep. 20, 2022 USD ($) | May 31, 2019 a | Jul. 31, 2017 a | |
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares | $ 0.001 | $ 0.001 | ||||
Operating Lease, Expense | $ 2.3 | $ 2.1 | ||||
Corporate Headquarters in Hayward, California [Member] | ||||||
Lessee, Operating Lease, Term of Contract (Year) | 5 years | |||||
Area of Real Estate Property (Acre) | a | 15,700 | |||||
Corporate Headquarters in Hayward, California [Member] | Expansion Premises 1 [Member] | ||||||
Area of Real Estate Property (Acre) | a | 13,300 | |||||
Corporate Headquarters in Hayward, California [Member] | Expansion Premises 2 [Member] | ||||||
Area of Real Estate Property (Acre) | a | 21,300 | |||||
Robert W. Duggan [Member] | Private Placement [Member] | ||||||
Stock Issued During Period, Shares, New Issues (in shares) | shares | 10,022,937 | |||||
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares | $ 0.001 | |||||
Shares Issued, Price Per Share (in dollars per share) | $ / shares | $ 6.51 | |||||
Two Thousand Twenty Two Loan Agreement [Member] | Robert W. Duggan [Member] | ||||||
Debt Instrument, Face Amount | $ 65 | |||||
Debt Instrument Quarterly Interest Rate | 5 | |||||
Debt Instrument, Increase, Accrued Interest | 1.7 | |||||
Interest Expense | $ 1.1 | |||||
Loan Agreement [Member] | ||||||
Debt Instrument, Decrease, Forgiveness | $ 65 | |||||
Interest Payable | $ 0.2 |
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, 2023 | Dec. 31, 2022 | |
Operating right-of-use assets | $ 7,256 | $ 8,062 |
Lease liability, current | 1,058 | 896 |
Lease liability, less current portion | 8,086 | 9,144 |
Total lease liabilities | 9,144 | 10,040 |
Cash paid for operating lease liabilities | 1,845 | $ 1,806 |
2024 | 1,910 | |
2025 | 1,977 | |
2026 | 2,046 | |
2027 | 2,117 | |
2028 | 2,191 | |
Thereafter | 1,883 | |
Total lease payments | 12,124 | |
Less imputed interest | $ (2,980) | |
Weighted-average remaining lease term (Year) | 5 years 9 months 29 days | |
Weighted-average discount rate | 10% |
Note 14 - Restructuring Charg_2
Note 14 - Restructuring Charges (Details Textual) - Employee Severance [Member] $ in Millions | 1 Months Ended | ||
Feb. 28, 2023 USD ($) | Sep. 30, 2022 USD ($) | Mar. 31, 2022 USD ($) | |
Restructuring and Related Cost, Number of Positions Eliminated | 7 | ||
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] | |||
Restructuring Charges, Total | $ 0.1 | ||
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) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Defined Contribution Plan, Employer Discretionary Contribution Amount | $ 0 | $ 0 |
Note 17 - Subsequent Events (De
Note 17 - Subsequent Events (Details Textual) - The 2017 Inducement Equity Incentive Plan [Member] - shares | 1 Months Ended | |
Mar. 31, 2024 | May 31, 2021 | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares) | 1,000,000 | |
Subsequent Event [Member] | ||
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares) | 2,000,000 |