Document and Entity Information
Document and Entity Information - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2023 | Mar. 01, 2024 | Jun. 30, 2023 | |
Cover [Abstract] | |||
Document Type | 10-K | ||
Amendment Flag | false | ||
Document Period End Date | Dec. 31, 2023 | ||
Document Fiscal Year Focus | 2023 | ||
Document Fiscal Period Focus | FY | ||
Entity Registrant Name | SOLENO THERAPEUTICS INC | ||
Entity Central Index Key | 0001484565 | ||
Current Fiscal Year End Date | --12-31 | ||
Entity Well-known Seasoned Issuer | Yes | ||
Entity Current Reporting Status | Yes | ||
Entity Voluntary Filers | No | ||
Entity Interactive Data Current | Yes | ||
Entity Filer Category | Non-accelerated Filer | ||
Entity Small Business | true | ||
Entity Shell Company | false | ||
Entity Emerging Growth Company | false | ||
Document Annual Report | true | ||
Document Transition Report | false | ||
Entity File Number | 001-36593 | ||
Entity Tax Identification Number | 77-0523891 | ||
Entity Address, Address Line One | 203 Redwood Shores Parkway | ||
Entity Address, Address Line Two | Suite 500 | ||
Entity Address, City or Town | Redwood City | ||
Entity Address, State or Province | CA | ||
Entity Address, Postal Zip Code | 94065 | ||
City Area Code | 650 | ||
Local Phone Number | 213-8444 | ||
Entity Incorporation, State or Country Code | DE | ||
Document Financial Statement Error Correction [Flag] | false | ||
Entity Common Stock, Shares Outstanding | 32,460,579 | ||
Entity Public Float | $ 33.1 | ||
Auditor Name | Marcum LLP | ||
Auditor Location | San Francisco, CA | ||
Auditor Firm ID | 688 | ||
Title of 12(b) Security | Common Stock, $0.001 par value | ||
Trading Symbol | SLNO | ||
Security Exchange Name | NASDAQ | ||
Documents Incorporated by Reference | DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s Definitive Proxy Statement to be filed with the Commission pursuant to Regulation 14A in connection with the registrant’s 2024 Annual Meeting of Stockholders, to be filed subsequent to the date hereof, are incorporated by reference into Part III of this Report. Such Definitive Proxy Statement will be filed with the Securities and Exchange Commission not later than 120 days after the conclusion of the registrant’s fiscal year ended December 31, 2023. Except with respect to information specifically incorporated by reference in this Form 10-K, the Proxy Statement is not deemed to be filed as part of this Form 10-K. |
Consolidated Balance Sheets
Consolidated Balance Sheets - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022 |
Current assets | ||
Cash and cash equivalents | $ 169,681 | $ 14,602 |
Prepaid expenses and other current assets | 1,677 | 1,045 |
Total current assets | 171,358 | 15,647 |
Long-term assets | ||
Property and equipment, net | 12 | 26 |
Operating lease right-of-use assets | 407 | 131 |
Intangible assets, net | 8,749 | 10,693 |
Other long-term assets | 165 | |
Total assets | 180,691 | 26,497 |
Current liabilities | ||
Accounts payable,net | 3,149 | 1,777 |
Accrued compensation | 3,135 | 1,675 |
Accrued clinical trial site costs | 3,393 | 3,222 |
Operating lease liabilities | 273 | 155 |
Other current liabilities | 1,555 | 484 |
Total current liabilities | 11,505 | 7,313 |
Long-term liabilities | ||
Contingent liability for Essentialis purchase price | 11,549 | 8,835 |
Long-term lease liabilities | 130 | 0 |
Total liabilities | 23,184 | 16,149 |
Commitments and contingencies (Note 8) | ||
Stockholders’ equity | ||
Preferred stock, $0.001 par value; 10,000,000 shares authorized, no shares issued and outstanding | ||
Common stock, $0.001 par value, 100,000,000 shares authorized, 31,678,159 and 8,159,382 shares issued and outstanding at December 31, 2023 and December 31, 2022, respectively. | 32 | 8 |
Additional paid-in-capital | 433,885 | 247,762 |
Accumulated deficit | (276,410) | (237,422) |
Total stockholders' equity | 157,507 | 10,348 |
Total liabilities and stockholders'equity | 180,691 | 26,497 |
2018 PIPE Warrant Liability [Member] | ||
Long-term liabilities | ||
Warrant liability | $ 0 | $ 1 |
Consolidated Balance Sheets (Pa
Consolidated Balance Sheets (Parenthetical) - $ / shares | Dec. 31, 2023 | Dec. 31, 2022 |
Statement of Financial Position [Abstract] | ||
Preferred stock, par value | $ 0.001 | $ 0.001 |
Preferred stock, shares authorized | 10,000,000 | 10,000,000 |
Preferred stock, shares issued | 0 | 0 |
Preferred stock, shares outstanding | 0 | 0 |
Common stock, par value (in dollars per share) | $ 0.001 | $ 0.001 |
Common stock, shares authorized | 100,000,000 | 100,000,000 |
Common stock, shares issued | 31,678,159 | 8,159,382 |
Common stock, shares outstanding | 31,678,159 | 8,159,382 |
Consolidated Statements of Oper
Consolidated Statements of Operations - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Operating expenses | ||
Research and development | $ 25,189 | $ 15,265 |
General and administrative | 13,481 | 9,844 |
Change in fair value of contingent consideration | 2,714 | (712) |
Total operating expenses | 41,384 | 24,397 |
Operating loss | (41,384) | (24,397) |
Other income (expense), net | ||
Change in fair value of warrant liability | (182) | 30 |
Interest income | 2,578 | 300 |
Total other income (expense), net | 2,396 | 330 |
Net loss | $ (38,988) | $ (24,067) |
Net loss per common share basic | $ (2.36) | $ (2.87) |
Net loss per common share diluted | $ (2.36) | $ (2.87) |
Weighted-average common shares outstanding used to calculate basic net loss per common share | 16,492,132 | 8,397,088 |
Weighted-average common shares outstanding used to calculate diluted net loss per common share | 16,492,132 | 8,397,088 |
Consolidated Statements of Stoc
Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands | Total | Public Offering [Member] | Common Stock [Member] | Common Stock [Member] Public Offering [Member] | Paid-In Capital [Member] | Paid-In Capital [Member] Public Offering [Member] | Accumulated Deficit [Member] |
Balances at beginning at Dec. 31, 2021 | $ 17,793 | $ 5 | $ 231,143 | $ (213,355) | |||
Balances at beginning (shares) at Dec. 31, 2021 | 5,324,287 | ||||||
Increase (Decrease) in Stockholders' Equity [Roll Forward] | |||||||
Stock-based compensation | 2,530 | 2,530 | |||||
Issuance of restricted stock units under equity incentive plan (shares) | 18,650 | ||||||
Tax withholding payments for net share-settled equity awards | (16) | (16) | |||||
Tax withholding payments for net share-settled equity awards (shares) | (3,683) | ||||||
Sale of common stock and issuance of common stock warrants and pre-funded common stock warrants, net of issuance costs | 342 | $ 9,327 | $ 3 | 342 | $ 9,324 | ||
Sale of common stock and issuance of common stock warrants and pre-funded common stock warrants, net of issuance costs (shares) | 104,773 | 2,666,667 | |||||
Sale of pre-funded warrants in public offering, net of issuance costs | 4,439 | 4,439 | |||||
Exercise of common stock warrants (shares) | 48,688 | ||||||
Net loss | (24,067) | (24,067) | |||||
Balances at ending at Dec. 31, 2022 | 10,348 | $ 8 | 247,762 | (237,422) | |||
Balances at end (shares) at Dec. 31, 2022 | 8,159,382 | ||||||
Increase (Decrease) in Stockholders' Equity [Roll Forward] | |||||||
Stock-based compensation | 5,809 | 5,809 | |||||
Issuance of restricted stock units under equity incentive plan | 136 | 136 | |||||
Issuance of restricted stock units under equity incentive plan (shares) | 423,248 | ||||||
Tax withholding payments for net share-settled equity awards (shares) | (128) | ||||||
Sale of common stock and issuance of common stock warrants and pre-funded common stock warrants, net of issuance costs | 137,857 | $ 6 | 137,851 | ||||
Sale of common stock and issuance of common stock warrants and pre-funded common stock warrants, net of issuance costs (shares) | 7,047,397 | ||||||
Exercise of common stock warrants | 41,998 | $ 17 | 41,981 | ||||
Exercise of common stock warrants (shares) | 15,961,267 | ||||||
Exercise of stock options | 347 | $ 1 | 346 | ||||
Exercise of stock options (shares) | 86,993 | ||||||
Net loss | (38,988) | (38,988) | |||||
Balances at ending at Dec. 31, 2023 | $ 157,507 | $ 32 | $ 433,885 | $ (276,410) | |||
Balances at end (shares) at Dec. 31, 2023 | 31,678,159 |
Consolidated Statements of St_2
Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Less transaction costs | $ 8,449 | |
Issuance of common stock, warrants | $ 182 | $ (30) |
Warrants [Member] | ||
Less transaction costs | 333 | |
Common Stock [Member] | ||
Less transaction costs | 10 | |
Common Stock [Member] | Public Offering [Member] | ||
Less transaction costs | $ 701 |
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 | $ (38,988) | $ (24,067) |
Adjustments to reconcile net loss to net cash used in operating activities: | ||
Depreciation and amortization | 1,958 | 1,964 |
Noncash lease expense | 321 | 290 |
Stock-based compensation expense | 5,945 | 2,530 |
Change in fair value of common stock warrants | 182 | (30) |
Change in fair value of contingent consideration | 2,714 | (712) |
Change in operating assets and liabilities: | ||
Prepaid expenses, other current assets and other assets | (837) | 113 |
Accounts payable | 1,372 | (1,477) |
Accrued compensation | 1,460 | 947 |
Accrued clinical trial site costs | 171 | (198) |
Operating lease liabilities | (309) | (302) |
Other liabilities | 1,071 | 161 |
Net cash used in operating activities | (24,940) | (20,781) |
Cash flows from investing activities: | ||
Purchases of property and equipment | 0 | (13) |
Net cash used in investing activities | 0 | (13) |
Cash flows from financing activities: | ||
Proceeds from sale of common stock, common stock warrants and pre-funded stock warrants, net of issuance costs | 137,857 | 14,108 |
Proceeds from exercise of common stock warrants and pre-funded stock warrants, net of costs | 41,815 | 0 |
Proceeds from stock option exercises | 347 | 0 |
Tax withholding payments for net share-settled equity awards | 0 | (16) |
Net cash provided by financing activities | 180,019 | 14,092 |
Net increase (decrease) in cash and cash equivalents | 155,079 | (6,702) |
Cash and cash equivalents, beginning of period | 14,602 | 21,304 |
Cash and cash equivalents, end of period | 169,681 | 14,602 |
Supplemental disclosure of non-cash investing and financing information | ||
Operating lease right-of-use assets obtained in exchange for operating lease obligations | 597 | $ 0 |
Non-cash exercise of 2018 PIPE Warrants | $ 183 |
Overview
Overview | 12 Months Ended |
Dec. 31, 2023 | |
Accounting Policies [Abstract] | |
Overview | Note 1. Overview Soleno Therapeutics, Inc. (the Company or Soleno) is focused on the development and commercialization of novel therapeutics for the treatment of rare diseases. Its lead candidate is DCCR (Diazoxide Choline) Extended-Release tablets, a once-daily oral tablet for the treatment of Prader-Willi Syndrome (PWS). DCCR has received orphan designation for the treatment of PWS in the United States (U.S.) as well as in the European Union (E.U.). The Company incorporated in the State of Delaware on August 25, 1999, and is located in Redwood City, California. It initially established its operations as Capnia, a diversified healthcare company that developed and commercialized innovative diagnostics, devices and therapeutics addressing unmet medical needs. During 2017, the Company merged with Essentialis, Inc (Essentialis) and subsequently received stockholder approval to amend its Amended and Restated Certificate of Incorporation to change its name from “Capnia, Inc.” to “Soleno Therapeutics, Inc.”. Essentialis was a privately held clinical-stage company focused on the development of breakthrough medicines for the treatment of rare diseases where there is increased mortality and risk of cardiovascular and endocrine complications. After the merger, the Company’s primary focus has been the development and commercialization of novel therapeutics for the treatment of rare diseases and the Company divested all prior business efforts. |
Liquidity
Liquidity | 12 Months Ended |
Dec. 31, 2023 | |
Cash and Cash Equivalents [Abstract] | |
Liquidity | Note 2. Liquidity The Company had a net loss of $ 39.0 million during 2023 and has an accumulated deficit of $ 276.4 million at December 31, 2023 resulting from having incurred losses since its inception. The Company had $ 169.7 million of cash and cash equivalents on hand at December 31, 2023 and used $ 24.9 million of cash in its operating activities during 2023. The Company has financed its operations principally through issuance of equity securities. On October 2, 2023, the Company closed a public and concurrent private financing with gross proceeds of $ 129.0 million. In December 2022, the Company entered into a Securities Purchase Agreement providing for the sale of up to $ 60.0 million in warrants (Tranche A and Tranche B) and the common stock issuable upon the exercise thereof. The Company completed the closing of the sale and issued both tranches of warrants for $ 10.0 million in May 2023. The announcement of positive top-line data from the randomized withdrawal period of Study C602 triggered the mandatory exercise of the Tranche A warrants, and as of December 31, 2023, the Company had received $ 15.0 million. Certain investors exercised their Tranche B warrants and the Company has received $ 18.1 million as of December 31, 2023. The receipt of the exercise price of the remaining Tranche B warrants for up to $ 16.9 million is contingent upon the exercise of such warrants. The Company also received $ 9.3 million in gross proceeds from the exercise of certain March 2022 warrants during 2023. The Company expects to continue incurring losses for the foreseeable future. However, the Company expects that its current cash and cash equivalents balances will be sufficient to enable the Company to meet its obligations for at least the next twelve months from the date of this filing. |
Basis of Presentation and Summa
Basis of Presentation and Summary of Significant Accounting Policies | 12 Months Ended |
Dec. 31, 2023 | |
Accounting Policies [Abstract] | |
Basis of Presentation and Summary of Significant Accounting Policies | Note 3. Basis of Presentation and Summary of Significant Accounting Policies Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP), and the applicable rules and regulations of the Securities and Exchange Commission (SEC). Certain reclassifications on the consolidated statements of cash flows have been made to conform to current period presentation. The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. Reverse Stock Split On June 1, 2022, the stockholders of the Company approved a reverse stock split of its common stock at a ratio of one-for-fifteen , to be effected at the sole discretion of the Company’s Board of Directors as described in the proxy statement filed with the SEC on April 21, 2022. The implementation of the reverse stock split was approved by the Company’s Board of Directors on August 16, 2022. On August 26, 2022, the Company filed a certificate of amendment to its amended and restated certificate of incorporation in order to effectuate a reverse stock split of the Company’s issued and outstanding common stock on a one-for-fifteen basis. All common share and per share data are retrospectively restated to give effect of the split for all periods presented herein. After giving eff ect to the reverse stock split, the total number of shares of all classes of capital stock that the Corporation is authorized to issue is 110,000,000 shares, consisting of 100,000,000 shares of common stock, having a par value of $ 0.001 and 10,000,000 shares of preferred stock, having a par value of $ 0.001 . Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities, and reported amounts of expenses in the financial statements and accompanying notes. Actual results could differ from those estimates. Key estimates in the financial statements include the valuation of deferred income tax assets, the valuation of financial instruments, stock-based compensation, accrued costs for services rendered in connection with third-party contractor clinical trial activities, and the valuation of contingent liabilities for the purchase price of assets obtained through acquisition. Concentration of Credit Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents at U.S. banking institutions. At December 31, 2023, the majority of the Company’s funds were invested with two separate financial institutions and at times these balances may exceed the federally-insured limits. Operating cash in excess of federally-insured limits is custodied at a separate financial institution with an overnight sweep feature into a U.S. government money market fund. As of December 31, 2022, the Company’s funds were invested in one financial institution which at times may exceed the federally insured limit. Segments The Company operates in one segment. Management uses one measurement of profitability and does not segregate its business for internal reporting, making operating decisions, and assessing financial performance. All long-lived assets are maintained in the U.S. Cash and Cash Equivalents The Company considers all highly liquid investments, including its money market funds, purchased with an original maturity of three months or less to be cash equivalents. The Company’s cash and cash equivalents are held primarily in institutions in the U.S. and include deposits in a money market funds which were unrestricted as to withdrawal or use. Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consist of payments primarily related to clinical trials, insurance and short-term deposits. Prepaid expenses are initially recorded upon payment and are expensed as goods or services are received. Property and Equipment, Net Property and equipment are stated at cost net of accumulated depreciation and amortization calculated using the straight-line method over the estimated useful lives of the assets, generally between three and five years . Leasehold improvements are amortized on a straight-line basis over the lesser of their useful life or the remaining term of the lease. Maintenance and repairs are charged to expense as incurred, and improvements are capitalized. When assets are retired or otherwise disposed of, the cost and accumulated depreciation are removed from the balance sheet and any resulting gain or loss is reflected in operations in the period realized. Leases The Company determines whether an arrangement is a lease at inception. Specifically, it considers whether it controls the underlying asset and has the right to obtain substantially all the economic benefits or outputs from the asset. If the contractual arrangement contains a lease, the Company then determines whether it is an operating or finance lease. Right-of-Use (ROU) assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at commencement date based on the present value of lease payments over the lease term. Lease expense for operating lease payments is recognized on a straight-line basis over the lease term. Finance lease classification results in a front-loaded expense recognition pattern over the lease term as it recognizes interest expense and amortization expense as separate components of lease expense. The Company does not separate lease components from non-lease components for all classes of underlying assets, and instead accounts for the lease and non-lease components as a single component. Variable lease payments are recognized as they are incurred and primarily include common area maintenance, utilities, real estate taxes, insurance and other operating costs that are passed on from the lessor in proportion to the space leased by the Company. The Company does not recognize lease assets and lease liabilities for leases with an original lease term of less than one year. Long-Lived Assets The Company reviews its long-lived assets for impairment annually and whenever events or changes in circumstances indicate that the carrying amount of the assets may not be fully recoverable. The Company evaluates assets for potential impairment by comparing estimated future undiscounted net cash flows to the carrying amount of the asset. If the carrying amount of the assets exceeds the estimated future undiscounted cash flows, impairment is measured based on the difference between the carrying amount and the fair value of the assets. Intangible Assets In March 2017, the Company completed the acquisition of Essentialis in accordance with the merger agreement by and between the Company and Essentialis dated December 22, 2016 (the “Merger Agreement”). The merger transaction was accounted for as an asset acquisition under the acquisition method of accounting and accordingly, the value of $ 22.0 million was assigned to the identifiable intangible asset relating to the patent for DCCR, which patent expires in June 2028. Intangible assets with finite lives are amortized on a straight-line basis over their estimated useful lives, which for the patent is 11 years . The useful life of the intangible asset is evaluated each reporting period to determine whether events and circumstances warrant a revision to the remaining useful life. Research and Development Research and development costs are charged to operations as incurred. Research and development costs consist primarily of salaries, benefits, bonus, share-based compensation, consultant fees, certain facility costs and other costs associated with clinical trials. Clinical trial costs are a significant component of research and development expenses and include costs associated with third-party contractors and other vendors. Invoicing from third-party contractors for services performed can often occur several months later. The Company accrues the costs incurred for clinical trial activities as measured by patient progression and the timing of various aspects of the trial. For other services the Company accrues the costs in connection with third-party contractor activities based on its estimate of fees and costs associate with the contract that were rendered during the period and they are expensed as incurred. Costs to acquire technologies to be used in research and development that have not reached technological feasibility and have no alternative future use are expensed to research and development costs when incurred. Change in fair value of contingent consideration The Company recorded the value of contingent future consideration to be paid for the acquisition of Essentialis as a liability in March 2017 at the date of the acquisition. The changes in value of the liability for the contingent consideration since the acquisition date are recorded as operating expense in the consolidated statements of operations. Income Taxes The Company accounts for income taxes using the asset and liability method. Under this method, deferred income tax assets and liabilities are recorded based on the estimated future tax effects of differences between the amounts at which assets and liabilities are recorded for financial reporting purposes and the amounts recorded for income tax purposes. A valuation allowance is provided against the Company’s deferred income tax assets when their realization is not reasonably assured. The Company assesses all material positions taken in any income tax return, including all significant uncertain positions, in all tax years that are still subject to assessment or challenge by relevant taxing authorities. Assessing an uncertain tax position begins with the initial determination of the position’s sustainability and is measured at the largest amount of benefit that is greater than fifty percent likely of being realized upon ultimate settlement. As of each balance sheet date, unresolved uncertain tax positions must be reassessed, and the Company will determine whether (i) the factors underlying the sustainability assertion have changed and (ii) the amount of the recognized tax benefit is still appropriate. The recognition and measurement of tax benefits requires significant judgment. Judgments concerning the recognition and measurement of a tax benefit might change as new information becomes available. Common Stock Purchase Warrants and Other Derivative Financial Instruments The Company classifies common stock purchase warrants and other free standing derivative financial instruments as equity if the contracts (i) require physical settlement or net-share settlement or (ii) give the Company a choice of net-cash settlement or settlement in its own shares (physical settlement or net-share settlement). The Company classifies any contracts that (i) require net-cash settlement (including a requirement to net cash settle the contract if an event occurs and if that event is outside the control of the Company), (ii) give the counterparty a choice of net-cash settlement or settlement in shares (physical settlement or net-share settlement), or (iii) contain reset provisions as either an asset or a liability. The Company assesses classification of its freestanding derivatives at each reporting date to determine whether a change in classification between equity and liabilities is required. The Company determined that certain freestanding derivatives, which principally consist of 2018 PIPE Warrants, do not satisfy the criteria for classification as equity instruments due to the existence of certain cash settlement features that are not within the sole control of the Company or variable settlement provision that cause them to not be indexed to the Company’s own stock. The Company classified the 2018 PIPE Warrants at their fair value and re-measured them at each balance sheet date until they were exercised or expired. Any changes in the fair value were recognized as Other income (expense) in the consolidated statements of operations. The 2018 PIPE Warrants expired in December 2023. Stock-Based Compensation Stock-based compensation costs related to stock options and restricted stock units granted to employees, nonemployees and directors are measured at the date of grant based on the estimated fair value of the award. For restricted stock units this fair value is based on the Company’s common stock price on the grant date. The Company estimates the grant date fair value of stock options, and the resulting stock-based compensation expense, using the Black-Scholes option-pricing model. The grant date fair value of stock-based awards is recognized on a straight-line basis over the requisite service period, which is generally the vesting period for service-based awards. For performance-based awards the requisite service period is the longest explicit, implicit or derived service period based on management’s estimate of the probability of the performance criteria being satisfied, adjusted at each balance sheet date. The Black-Scholes option-pricing model requires the use of highly subjective assumptions to estimate the fair value of stock-based awards. If the Company had made different assumptions, its stock-based compensation expense, net loss and net loss per share of common stock could have been significantly different. These assumptions include: • Expected volatility: We calculated the estimated volatility rate for stock options granted based on the volatility of our common stock for a historical period equal to the expected life of the stock options. • Expected life: Due to the lack of historical exercise history, the expected life of the Company’s service-based stock options is determined utilizing the “simplified method”, based on the average of the contractual term of the options and the weighted-average vesting period. The expected life for performance-based options is determined based on consideration of the contractual term of the stock options, an estimate of the date the performance criteria would be met and expectations of employee behavior. • Risk-free rate: The risk-free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected time to liquidity. • Expected divided yield: The Company has never declared or paid any cash dividends and does not presently plan to pay cash dividends in the foreseeable future. Consequently, it used an expected dividend yield of zero . The Company accounts for forfeitures as they occur. Recent Adopted Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (FASB) or other standard setting bodies that are adopted by the Company as of the specified effective date . In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures, which amends the guidance in ASC 740, Income Taxes. This ASU is intended to improve the transparency of income tax disclosures by requiring (1) consistent categories and greater disaggregation of information in the rate reconciliation and (2) income taxes paid disaggregated by jurisdiction. It also includes certain other amendments to improve the effectiveness of income tax disclosures. This ASU is effective for fiscal years beginning after December 15, 2024. Adoption is permitted either prospectively or retrospectively, and the Company will adopt this ASU on a prospective basis. The Company is currently evaluating the impact of adopting this ASU on its consolidated financial statements and disclosures. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses of Financial Instruments, which, together with subsequent amendments, amends the requirement on the measurement and recognition of expected credit losses for financial assets held. ASU 2016-13 is effective for the Company for the annual periods beginning after December 15, 2022, including interim periods within those fiscal years, with early adoption permitted. The Company adopted this ASU effective January 1, 2023 . There was no impact on the Company's financial statements upon the adoption of this ASU. Other accounting standards that have been issued or proposed by FASB or other standards-setting bodies that do not require adoption until a future date are not currently expected to have a material impact on the Company’s financial statements upon adoption. |
Fair Value of Financial Instrum
Fair Value of Financial Instruments | 12 Months Ended |
Dec. 31, 2023 | |
Fair Value Disclosures [Abstract] | |
Fair Value of Financial Instruments | Note 4. Fair Value of Financial Instruments The carrying value of the Company’s cash, cash equivalents and accounts payable, approximate fair value due to the short-term nature of these items. Fair value is defined as the exchange price that would be received for an asset or an exit price paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The fair value hierarchy defines a three-level valuation hierarchy for disclosure of fair value measurements as follows: • Level I — Unadjusted quoted prices in active markets for identical assets or liabilities; • Level II — Inputs other than quoted prices included within Level I that are observable, unadjusted quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and • Level III — Unobservable inputs that are supported by little or no market activity for the related assets or liabilities. The categorization of a financial instrument within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The following table sets forth the Company’s financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands): Fair Value Measurements at December 31, 2023 Total Level 1 Level 2 Level 3 Liabilities Essentialis purchase price contingency liability $ 11,549 $ - $ - $ 11,549 Fair Value Measurements at December 31, 2022 Total Level 1 Level 2 Level 3 Liabilities 2018 PIPE Warrant liability $ 1 $ — $ — $ 1 Essentialis purchase price contingency liability 8,835 — — 8,835 Total common stock warrant and contingent $ 8,836 $ — $ — $ 8,836 The Company’s estimated fair value of the 2018 PIPE Warrants was calculated using a Black-Scholes pricing model. The Black-Scholes pricing model requires the input of highly subjective assumptions including the expected stock price volatility, the expected term, the expected dividend yield and the risk-free interest rate. The 2018 PIPE Warrants expired on December 21, 2023. Based on the terms of the completed merger with Essentialis on March 7, 2017, the Company is obligated to make cash earnout payments of up to a maximum of $ 21.2 million to the former Essentialis stockholders. The fair value of the Essentialis purchase price contingent liability is estimated using scenario-based methods based upon the Company’s analysis of the likelihood of obtaining specified approvals from the FDA as well as achieving two commercial sales milestones of $ 100 million and $ 200 million in cumulative revenue . The Level 3 estimates are based, in part, on subjective assumptions. In determining the likelihood of this occurring, the analysis relied on published research relating to clinical development success rates. Based on management’s assessment, an 88 % and a 72 % probability of achieving all three milestones was determined to be reasonable as of December 31, 2023 and December 31, 2022, respectively. During the periods presented, the Company has not changed the manner in which it values its Essentialis purchase price contingent liability. The Company recognizes transfers between levels of the fair value hierarchy as of the end of the reporting period. There were no transfers within the hierarchy during the periods presented. The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 assets and liabilities (dollars in thousands): 2018 PIPE Warrants Purchase Price Number of Contingent Warrants Liability Liability Balance at December 31, 2021 34,241 $ 31 $ 9,547 Change in value of 2018 PIPE Warrants — ( 30 ) - Change in value of contingent liability — — ( 712 ) Balance at December 31, 2022 34,241 $ 1 $ 8,835 Change in value of 2018 PIPE Warrants — 419 — Exercise of 2018 PIPE Warrants ( 21,789 ) ( 183 ) — Expiration of 2018 PIPE Warrants ( 12,452 ) ( 237 ) — Change in value of contingent liability — — 2,714 Balance at December 31, 2023 0 $ - $ 11,549 |
Other Financial Statement Detai
Other Financial Statement Details | 12 Months Ended |
Dec. 31, 2023 | |
Other Financial Statement Details Disclosure [Abstract] | |
Other Financial Statement Details | Note 5. Other Financial Statement Details Property and Equipment, Net Property and equipment are summarized in the following table (in thousands): December 31, December 31, Computer hardware $ 72 $ 72 Furniture and fixtures 29 29 101 101 Less accumulated depreciation and amortization ( 89 ) ( 75 ) Total $ 12 $ 26 Depreciation expense was approximately $ 14 thousand and $ 20 thousand for the years ended December 31, 2023 and December 31, 2022, respectively. Intangible Assets, Net Intangible assets consist of the following (in thousands): December 31, 2023 December 31, 2022 Amount Accumulated Net Amount Accumulated Net Patents and merger costs $ 22,003 $ ( 13,254 ) $ 8,749 $ 22,003 $ ( 11,310 ) $ 10,693 Future amortization expense for intangible assets over their remaining useful lives is as follows (in thousands): Year ending December 31 Patents and 2024 1,944 2025 1,944 2026 1,944 2027 1,944 2028 and thereafter 973 Total $ 8,749 Amortization expense was $ 1.9 million for the year ended December 31, 2023 and 2022. |
Warrants
Warrants | 12 Months Ended |
Dec. 31, 2023 | |
Text Block [Abstract] | |
Warrants | Note 6. Warrants The Company has issued multiple warrant series, of which the 2018 PIPE Warrants were determined to be liabilities pursuant to the guidance established by ASC 815 Derivatives and Hedging. Warrants Issued as Part of the Units in the 2018 PIPE Offering The 2018 PIPE Warrants were issued on December 19, 2018 in the 2018 PIPE Offering, pursuant to a Warrant Agreement with each of the investors in the 2018 PIPE Offering, and prior to their expiration on December 21, 2023, entitled the holders to purchase 34,241 shares of the Company’s common stock at an exercise price equal to $ 30.00 per share, subject to adjustments. In the event of a change of control of the Company, the holders of unexercised warrants had the option to present their unexercised warrants to the Company, or its successor, to be purchased by the Company, or its successor, in an amount equal to the per share value determined by the Black-Scholes methodology. Since the Company may have been obligated to settle the 2018 PIPE Warrants in cash, the Company classified the 2018 PIPE Warrants as long-term liabilities at their fair value and re-measured the warrants at each balance sheet date until they were exercised or expire. Any change in the fair value is recognized as Other income (expense) in the Company’s consolidated statements of operations. There were no 2018 PIPE Warrants outstanding at December 31, 2023 as the warrants were either exercised or expired, and the Company estimated the fair value of the liability for the 2018 PIPE Warrants at approximately $ 1 thousand at December 31, 2022. During 2023, 21,789 2018 PIPE Warrants were exercised for net proceeds of $ 0.2 million, and the Company issued 9,683 shares of common stock. The remaining 12,452 2018 PIPE Warrants expired. The increase of $ 0.2 million and the decrease of $ 30 thousand in the fair value of the liability for the 2018 PIPE Warrants during the years ended December 31, 2023 and 2022, respectively, was recorded as Other income in the consolidated statements of operations. The Company has calculated the fair value of the 2018 PIPE Warrants using a Black-Scholes option-pricing model. The following summarizes certain key assumptions used in estimating the fair values: December 31, Volatility 117 % Contractual term (years) 1.0 Expected dividend yield — % Risk-free rate 4.74 % The Black-Scholes option-pricing model requires the use of highly subjective assumptions to estimate the fair value of stock-based awards. These assumptions include the following estimates: • Volatility: The Company calculated the estimated volatility rate based on its historical volatility of the warrants. • Contractual term: The expected life of the warrants, which is based on the contractual term of the warrants. • Expected dividend yield: The Company has never declared or paid any cash dividends and does not currently plan to pay cash dividends in the foreseeable future. Consequently, the Company used an expected dividend yield of zero . • Risk-free rate: The risk-free interest rate is based on the U.S. Treasury rate for similar periods as the expected life of the warrants. |
Leases
Leases | 12 Months Ended |
Dec. 31, 2023 | |
Leases [Abstract] | |
Leases | Note 7. Leases Facility Leases The Company's operating lease for its headquarters facility office space in Redwood City, California began in June 2021 and expired in May 2023 . In April 2023, the Company entered into a twenty-four month lease extension commencing on June 1, 2023. The term of the lease extension expires in May 2025 . The Company’s operating lease ROU assets, current operating lease liabilities and long-term operating lease liabilities each appear as a separate line within the Company’s consolidated balance sheet. As of December 31, 2023 and December 31, 2022, the Company’s short-term liabilities were equal to $ 0.3 million and $ 0.2 million, respectively, and the long-term operating lease liabilities were equal to $ 0.1 million as of December 31, 2023. There were no long-term operating lease liabilities as of December 31, 2022. The Company recorded an increase to its right-of-use asset by $ 0.6 million and an increase to its lease liability by $ 0.6 million as a result of the lease extension. The weighted average discount rate related to the Company’s lease liabilities was 8.25 % as of December 31, 2023 over a remaining term of 17 months, and 9 % as of December 31, 2022 over the remaining term of 5 months. The discount rates were determined based on estimates of the Company's incremental borrowing rate, as the discount rates implicit in the Company’s leases cannot be readily determined. The components of lease expense were as follows (in thousands): Year Ended December 31, December 31, Operating lease cost: Operating lease cost $ 312 $ 324 Short-term lease cost 44 29 Total operating lease cost $ 356 $ 353 Supplemental cash flow information related to leases was as follows (in thousands): Year Ended December 31, December 31, Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 341 $ 354 The following is a schedule by year of future maturities of the Company’s operating lease liabilities as of December 31, 2023 (in thousands): 2024 287 2025 143 Total lease payments 430 Less interest ( 27 ) Total $ 403 |
Commitments and Contingencies
Commitments and Contingencies | 12 Months Ended |
Dec. 31, 2023 | |
Commitments and Contingencies Disclosure [Abstract] | |
Commitments and Contingencies | Note 8. Commitments and Contingencies In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for general indemnifications. The Company’s exposure under these agreements is unknown because it involves claims that may be made against the Company in the future but have not yet been made. The Company accrues a liability for such matters when it is probable that future expenditures will be made, and such expenditures can be reasonably estimated. |
Stockholders' Equity
Stockholders' Equity | 12 Months Ended |
Dec. 31, 2023 | |
Equity [Abstract] | |
Stockholders' Equity | Note 9. Stockholders’ Equity Convertible Preferred Stock The Company is authorized to issue 10,000,000 shares of Preferred Stock. Public Offering of Common Stock and Concurrent Private Placement of Common Stock and Pre-Funded Warrants On October 2, 2023, the Company closed an underwritten public offering of 3,450,000 shares of its common stock at a public offering of $ 20.00 per share, which included the exercise in full by the underwriters of their option to purchase additional shares. The gross proceeds of the public offering were $ 69.0 million, before deducting the underwriting discount and other offering expenses. Concurrently, the Company also completed the closing of approximately $ 60.0 million for 1,825,000 shares of its common stock and 1,175,000 pre-funded warrants in a private offering pursuant to a securities purchase agreement with certain investors, including entities affiliated with existing stockholders, at a price per share of common stock equal to the public offering price of $ 20.00 and a price per per-funded warrant of $ 19.99 . In aggregate, the Company received $ 129.0 million of gross proceeds less offering costs of $ 8.2 million The Company is not required under any circumstance to settle any of the pre-funded warrants for cash, and therefore classified the pre-funded warrants as permanent equity. Securities Purchase Agreement On December 16, 2022, the Company entered into a Securities Purchase Agreement for a private placement (Private Placement) with certain entities and members of management (collectively, Purchasers). Pursuant to the Securities Purchase Agreement, the Company agreed to sell to the Purchasers warrants to purchase up to an aggregate of 22,598,870 shares of the Company’s common stock, at a purchase price of $ 0.4425 per warrant. The closing of the Private Placement occurred on May 8, 2023 (the Issue Date), following the satisfaction of certain closing conditions, including the completion of enrollment in the randomized withdrawal period of Study C602. The Company received gross proceeds of $ 10.0 million for the sale and issuance of warrants to purchase common stock. The warrants were separated into two tranches with 8,598,870 Tranche A warrants with an exercise price of $ 1.75 and aggregate proceeds of up to approximately $ 15.0 million, and 14,000,000 Tranche B warrants with an exercise price of $ 2.50 and aggregate proceeds of up to $ 35.0 million. The Tranche A warrants were immediately exercisable and were required to be exercised within 30 days of announcement of positive top-line data from the randomized withdrawal period of Study C602. On September 26, 2023, the Company announced positive top-line data and subsequently received $ 15.0 million from the exercise of the Tranche A warrants. The Tranche B warrants are also immediately exercisable and expire upon the earlier of 3.5 years from the date of issuance or 30 days following receipt of FDA approval of DCCR for the treatment of PWS. During 2023, certain investors exercised their Tranche B warrants and the Company received $ 18.1 million. The receipt of the aggregate exercise price of up to $ 16.9 million for the remaining Tranche B warrants is contingent upon the exercise of such warrants. Underwritten Public Offering On March 31, 2022, the Company sold 2,666,667 shares of its common stock at a public offering price of $ 3.75 , and for certain investors, in lieu of common stock, pre-funded warrants (the March 2022 pre-funded warrants) to purchase 1,333,333 shares of its common stock at a public offering price $ 3.60 per pre-funded warrant, which represents the per share public offering price for the common stock less the $ 0.15 per share exercise price for each March 2022 pre-funded warrant. The March 2022 pre-funded warrants are immediately exercisable and may be exercised at any time until all of the March 2022 pre-funded warrants are exercised in full. Each share of common stock or March 2022 pre-funded warrant was sold together with one, immediately exercisable, common warrant (the 2022 common warrants) with a five-year term to purchase one share of common stock at an exercise price of $ 4.50 per share. The net proceeds of the offering were $ 13.8 million, after deducting the underwriting discount and other offering expenses. The Company is not required under any circumstance to settle any of the 2022 pre-funded warrants or the 2022 common warrants for cash, and therefore classified both types of warrants as permanent equity. In 2023, 2,070,934 March 2022 warrants were exercised for gross proceeds of $ 9.3 million and all 1,280,965 March 2022 pre-funded warrants were exercised using the cashless exercise option with no additional proceeds received by the Company. At the Market Offering In July 2021, the Company entered into a Controlled Equity Offering Sales Agreement under which the Company may sell shares of its common stock having an aggregate offering price of up to $ 25.0 million from time to time in any method permitted by law deemed to be an “at the market” Rule 415 under the Securities Act of 1933, as amended. As of December 31, 2023, the Company has sold 1,877,170 shares of common stock through the at the market program, totaling $ 7.4 million in net proceeds. The Controlled Equity Offering Sales Agreement was terminated in connection with the October 2, 2023 financing. Other Common Stock Warrants As of December 31, 2023, the Company had 6,804 common stock warrants outstanding from the 2010/2012 convertible notes, with an exercise price of $ 365.25 and expire in November 2024 . The Company also had outstanding 1,100 common stock warrants issued to the underwriter in the Company’s IPO, with an exercise price of $ 535.50 and a term of 10 years , expiring in November 2024 . As of December 31, 2023 and December 31, 2022, the following table summarizes the Company's outstanding common stock warrants: As of December 31, 2023 As of December 31, 2022 Number of Common Warrant Shares Weighted Average Exercise Price per Share Number of Common Warrant Shares Weighted Average Exercise Price per Share Expiration Date Common stock warrants 7,904 $ 388.94 7,904 $ 388.94 November 2024 2018 PIPE warrants — $ - 34,241 $ 30.00 December 2023 March 2022 Common warrants 1,929,066 $ 4.50 4,000,000 $ 4.50 March 2027 March 2022 Pre-funded warrants — $ - 1,280,965 $ 0.15 March 2027 May 2023 Tranche A Pre-funded warrants 2,758,281 $ 0.01 — $ — November 2026 May 2023 Tranche B warrants 6,750,000 $ 2.50 — $ — November 2026 (1) May 2023 Tranche B Pre-funded warrants 451,632 $ 0.01 — $ — November 2026 October 2023 Pre-funded warrants 1,175,000 $ 0.01 — $ — N/A Total 13,071,883 5,323,110 (1) Subject to earlier expiration as described above. Equity Incentive Plans 2014 Plan The Company maintains the 2014 Equity Incentive Plan (the 2014 Plan). Under the 2014 Plan the Company may grant stock options, stock appreciation rights, restricted stock, restricted stock units, performance units or performance shares to employees, directors, advisors, and consultants. Options granted under the 2014 Plan may be incentive stock options (ISOs) or nonqualified stock options (NSOs). ISOs may be granted only to Company employees, including officers and directors. The Board has the authority to determine to whom stock options will be granted, the number of options, the term, and the exercise price. Options are to be granted at an exercise price not less than fair value. For individuals holding more than 10 % of the voting rights of all classes of stock, the exercise price of an option will not be less than 110 % of fair value. Performance-based grants have vesting contingent upon the achievement of certain performance criteria related to the Company’s commercialization of its therapeutics. The contractual term of an option is no longer than five years for ISOs for which the grantee owns greater than 10% of the voting power of all classes of stock and no longer than ten years for all other options. The terms and conditions governing restricted stock units is at the sole discretion of the Board. On March 23, 2023, the Company filed a Registration Statement on Form S-8 which registered 238,329 shares available for grant and issuance under the 2014 Plan, all of which became available for grant and issuance under the 2014 Plan on January 1, 2023. On May 25, 2023, the stockholders approved the Amended and Restated 2014 Plan which included an increase of 1.8 million shares available for grant and issuance. As of December 31, 2023, a total of 1,465 shares were available for future grant under the 2014 Plan. Inducement Plan The Company maintains the 2020 Inducement Equity Incentive Plan (the Inducement Plan). The Inducement Plan provides for the grant of equity-based awards, including non-statutory stock options, restricted stock units, restricted stock, stock appreciation rights, performance shares and performance units, and its terms are substantially similar to the Company’s 2014 Equity Incentive Plan. In accordance with Rule 5635(c)(4) and Rule 5635(c)(3) of the Nasdaq Listing Rules, awards under the Inducement Plan may only be made to individuals not previously employees or non-employee directors of the Company (or following such individuals’ bona fide period of non-employment with the Company), as an inducement material to the individuals’ entry into employment with the Company, or, to the extent permitted by Rule 5635(c)(3) of the Nasdaq Listing Rules, in connection with a merger or acquisition. On March 23, 2023, the Company filed a Registration Statement on Form S-8 which registered 500,000 shares available for issuance under the Inducement Plan, all of which became available for grant and issuance under the Inducement Plan on February 17, 2023. As of December 31, 2023, a total of 445,668 shares were available for future grant under the Inducement Plan. Stock-based compensation expense The Company recognized stock-based compensation expense related to options and restricted stock units granted to employees, directors and consultants for the years ended December 31, 2023 and 2022 of $ 5.9 million and $ 2.5 million, respectively. The compensation expense is allocated on a departmental basis, based on the classification of the option holder. For the year ended December 31, 2023, the total income tax benefit related to stock-based compensation was $ 1.9 million, however, due to net operating losses and a full valuation allowance, no tax benefit was recognized in the financial statements. The total income tax benefit related to stock-based compensation for the year ended December 31, 2022 was zero . Stock compensation expense was recognized in the consolidated statements of operations as follows (in thousands): Year ended December 31, December 31, Research and development $ 2,434 $ 692 General and administrative 3,511 1,838 Total $ 5,945 $ 2,530 Stock Options The Company granted options to purchase 1,821,784 and 283,919 of the Company’s common stock during the years ended December 31, 2023 and 2022, respectively. There were no performance-based options granted in 2023 and 2022, respectively. The fair value of each award granted was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions: Year Ended December 31, December 31, Expected life (years) 5.3 - 6.1 5.5 - 6.0 Risk-free interest rate 3.5 %- 4.5 % 1.7 %- 3.1 % Volatility 98 %- 122 % 88 %- 95 % Dividend rate — % — % The Black-Scholes option-pricing model requires the use of highly subjective assumptions to estimate the fair value of stock-based awards. These assumptions include the following estimates: • Expected life: The expected life of stock options represents the period of time that the options are expected to be outstanding. Due to the lack of historical exercise history, the expected life of the Company’s service-based stock options has been determined utilizing the “simplified method”, based on the average of the contractual term of the options and the weighted-average vesting period. The expected life for the performance-based options was determined based on consideration of the contractual term of the stock options, an estimate of the date the performance criteria would be met and expectations of employee behavior. • Risk-free interest rate: The risk-free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected life of the stock options. • Volatility: The estimated volatility rate is based on the volatilities of the Company’s common stock for a historical period equal to the expected life of the stock options. • Dividend rate: The Company has never declared or paid any cash dividends and does not presently plan to pay cash dividends in the foreseeable future. Consequently, the Company used an expected dividend yield of zero . The following table summarizes stock option transactions for the years ended December 31, 2023 and 2022 as issued under the 2014 Plan and the Inducement Plan: Number of Weighted- Weighted Aggregate Intrinsic Value Outstanding Share (in years) (in thousands) Balance at December 31, 2021 408,329 $ 46.28 7.94 Options granted 283,919 3.56 Options canceled/forfeited ( 5,674 ) 19.31 Balance at December 31, 2022 686,574 $ 28.83 7.93 Options granted 1,821,784 6.18 Options exercised ( 89,993 ) 4.01 Options canceled/forfeited ( 48,700 ) 67.84 Balance at December 31, 2023 2,369,665 $ 11.56 8.72 $ 70,834 Options exercisable at December 31, 2023 797,988 $ 18.31 7.76 $ 20,320 Options vested and expected to vest at 2,346,707 $ 11.34 8.75 $ 70,834 The weighted-average grant date fair value of employee options granted was $ 5.04 and $ 2.62 pe r share for the years ended December 31, 2023 and December 31, 2022, respectively. At December 31, 2023 total unrecognized employee stock-based compensation for options that are expected to vest was $ 9.1 million, which is expected to be recognized over the weighted-average remaining vesting period of 2.5 years. Restricted Stock Units There were 420,710 and 8,965 restricted stock units granted by the Company during the years ended December 31, 2023 and December 31, 2022, respectively, to employees and certain directors. In 2023, 414,710 restricted stock units were granted to employees with a six-month vesting period, and all such restricted stock units vested during 2023. The restricted stock units granted to certain directors in 2022 were 100 % vested on the grant date and represent compensation for past board services. The shares were valued based on the Company’s common stock price on the grant date. The following table summarizes restricted stock unit transactions for the years ended December 31, 2023 and 2022 as issued under the 2014 Plan: Number of Weighted- Outstanding at December 31, 2021 29,050 $ 57.75 Restricted stock units granted 8,965 5.33 Restricted stock units vested ( 18,646 ) 32.55 Restricted stock units cancelled/forfeited ( 301 ) 57.85 Outstanding at December 31, 2022 19,068 $ 57.75 Restricted stock units granted 420,710 5.49 Restricted stock units vested ( 423,248 ) 6.43 Restricted stock units cancelled/forfeited ( 996 ) 5.25 Outstanding at December 31, 2023 15,534 $ 43.92 The weighted-average grant-date fair value of all restricted stock units granted was $ 5.49 and $ 5.33 per share during the year ended December 31, 2023 and 2022, respectively. The fair value of all restricted stock units vested during the year ended December 31, 2023 and 2022 was $ 12.0 million and $ 0.1 million, respectively. At December 31, 2023, total unrecognized employee stock-based compensation related to restricted stock units was $ 0.2 million, which is expected to be recognized over the weighted-average remaining vesting period of 0.2 years. 2014 Employee Stock Purchase Plan The Company’s board of directors and stockholders have adopted the 2014 Employee Stock Purchase Plan (the ESPP). The ESPP has become effective, and the board of directors will implement commencement of offers thereunder in its discretion. A total of 1,864 shares of the Company’s common stock has been made available for sale under the ESPP. In addition, the ESPP provides for annual increases in the number of shares available for issuance under the plan on the first day of each year beginning in the year following the initial date that the board of directors authorizes commencement, equal to the least of: • 1.0 % of the outstanding shares of the Company’s common stock on the first day of such year; • 3,729 shares; or • such amount as determined by the board of directors. As of December 31, 2023, there were no purchases by employees under this plan. |
Income Taxes
Income Taxes | 12 Months Ended |
Dec. 31, 2023 | |
Income Tax Disclosure [Abstract] | |
Income Taxes | Note 10. Income Taxes The geographical distribution of loss before income taxes are summarized below (in thousands): December 31, 2023 2022 United States $ ( 39,180 ) $ ( 24,173 ) Foreign 192 106 Loss before income taxes $ ( 38,988 ) $ ( 24,067 ) The provision for income tax benefit differs from the amount estimated by applying the statutory federal income tax rate to the operating loss due to the following (in thousands): December 31, 2023 2022 Tax (benefit) on the loss before income tax expense $ ( 8,187 ) $ ( 5,055 ) State tax (benefit) at statutory rate, net of federal ( 505 ) ( 527 ) Foreign rate differential 6 - Change in valuation allowance 8,934 5,702 Change in research and development credits ( 1,631 ) ( 652 ) Stock based compensation ( 600 ) ( 734 ) Change in fair value of warrants 38 ( 6 ) Change in fair value of contingent consideration 570 ( 150 ) Section 162(m) limitation 589 - Change in net operating loss true up 39 739 Change in capital losses — 405 Change in state rates 653 375 Other 94 ( 97 ) Provision for income tax benefit $ — $ — Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets and liabilities are as follows at December 31, 2023 and 2022 (in thousands): December 31, 2023 2022 Non-current deferred tax assets: Federal and state net operating loss carryforwards $ 51,481 $ 49,024 Research and other credits 6,352 4,146 Capitalized research and development 6,778 2,828 Reserves and accruals 655 547 Fixed assets 29 44 Capital loss carryover 432 555 Stock based compensation 2,013 2,682 Lease liability 85 42 Other deferred tax assets 54 72 Gross non-current deferred tax assets 67,879 59,940 Intangible assets ( 1,837 ) ( 2,888 ) Right-of-use assets ( 86 ) ( 35 ) Total non-current deferred tax liabilities ( 1,923 ) ( 2,923 ) Total deferred tax assets 65,956 57,017 Valuation allowance ( 65,956 ) ( 57,017 ) Net deferred tax assets $ — $ — The Company has recorded a full valuation allowance against its net deferred tax assets due to the uncertainty as to whether such assets will be realized. The valuation allowance increased by $ 8.9 million from December 31, 2022 to December 31, 2023 primarily due to the generation of current year net operating losses, research and development credits claimed, capitalized research and developments costs, and stock-based compensation. As of December 31, 2023, the Company had $ 206.7 million of federal, $ 111.0 million of state and $ 2.3 million of foreign net operating losses available to offset future taxable income. The Federal net operating loss carryforwards arising from years prior to 2018 began to expire in 2022, however post 2017 federal net operating loss carryforwards of $ 93.1 million may be carried forward indefinitely. The state net operating loss carryforwards will begin to expire in 2028 and the foreign net operating loss carryforward can be carried forward indefinitely, if not utilized. As of December 31, 2023, the Company also had $ 6.4 million of federal and $ 3.4 million of state research and development credit carryforwards. The federal research and development credit carryforward begin to expire in 2024 and the state research and development credit can be carried forward indefinitely. Beginning in fiscal year 2023, the Tax Cuts and Jobs Act of 2017 eliminates the option to deduct research and development expenditures currently and requires taxpayers to amortize such costs over a period of five or fifteen years . While it is possible that Congress may modify, defer, or repeal such provision, we have no assurance that the provision will be modified, deferred or repealed. Utilization of the net operating loss and tax credit carry forwards are subject to an annual limitation due to the ownership percentage change limitations provided by the Internal Revenue Code of 1986 and similar state provisions. The annual limitation may result in the expiration of the net operating loss before utilization. The Company completed Section 382 analysis through December 2016 and determined that an ownership change, as defined under Section 382 of the Internal Revenue Code, occurred in June 2016. The Company’s tax attributes are subject to an annual limitation of $ 0.5 million per year for federal purposes. For years ended after December 31, 2016, the utilization of net operating losses and tax credit carryforwards are subject to further limitation in the event an additional ownership change were to occur for tax purposes. The Company is currently in the process of analyzing whether there was an ownership change, as defined under Section 382 of the Internal Revenue Code, resulting from the issuance of new shares during 2018 through 2023 and expects that analysis to completed during 2024. As such, as of the date of these consolidated financial statements the Company is not able to determine the impact on the net operating loss (NOL) carryforwards, if any. U.S. taxes and foreign withholding taxes have not been provided on undistributed earnings for certain non-U.S. subsidiaries as of December 31, 2023, as the earnings, if any, are intended to be indefinitely reinvested. The following tables summarize the activities of gross unrecognized tax benefits (in thousands): December 31, 2023 2022 Beginning balance $ 1,936 $ 1,557 Increase related to current year tax positions 1,002 379 Ending balance $ 2,938 $ 1,936 The Company uses the “more likely than not” criterion for recognizing the tax benefit of uncertain tax positions and to establish measurement criteria for income tax benefits. The Company has determined it has $ 2.9 million of unrecognized assets and liabilities related to uncertain tax positions as of December 31, 2023. Changes in the unrecognized tax benefits within the next 12 months are expected to be similar to prior years and should not significantly increase or decrease. In the event the Company should need to recognize interest and penalties related to unrecognized tax liabilities, this amount will be recorded as a component of other expense. There were no unrecognized tax benefits that would impact the effective tax rate as of December 31, 2023 and December 31, 2022. As of December 31, 2023, unrecognized tax benefits of $ 2.9 million would be offset by a change in valuation allowance. The Company files income tax returns in the U.S. federal jurisdiction, certain state jurisdictions, United Kingdom and Ireland. In the normal course of business, the Company is subject to examination by federal, state, local and foreign jurisdictions, where applicable. In the U.S federal jurisdiction, tax years 2003 forward remain open to examination, in the state tax jurisdiction, years 2008 forward remain open to examination and in the foreign jurisdiction, years 2015 forward remain open to examination. The Company is currently not under audit by any federal, state, local or foreign jurisdiction. |
Net Loss per Share
Net Loss per Share | 12 Months Ended |
Dec. 31, 2023 | |
Earnings Per Share [Abstract] | |
Net Loss per Share | Note 11. Net Loss per Share Basic net loss per share is computed by dividing net loss by the weighted-average number of common shares outstanding during the period. Shares of common stock that are potentially issuable for little or no cash consideration at issuance, such as the Company's pre-funded warrants issued in March 2022 and October 2023 and in connection with the exercise of certain May 2023 Tranche A and Tranche B warrants, are considered outstanding common stock and are included in the calculation of basic and diluted net loss per share in connection with ASC 260 Earnings Per Shares . Diluted net loss per share is computed by dividing net loss by the weighted-average number of common stock outstanding and dilutive potential common stock that would be issued upon the exercise or vesting of common stock awards, restricted stock units and exercise of common stock warrants that are not pre-funded. The Company applies the two-class method to calculate basic and diluted earnings per share as its warrants issued in March 2022 and May 2023 are participating securities. However, the two-class method does not impact the net loss per share of common stock as the March 2022 and May 2023 common warrants issued do not participate in losses . For the years ended December 31, 2023 and 2022, the effect of issuing the respective potential common stock is anti-dilutive due to the net losses in those periods and therefore the number of shares used to compute basic and diluted net loss per share are the same in each of those periods. The following securities are included in the weighted-average common shares outstanding used to calculate basic and diluted net loss per common share: As of December 31, 2023 2022 Common stock 15,040,036 7,409,165 March 2022 pre-funded warrants 290,665 987,923 May 2023 Tranche A pre-funded exchange warrants 778,904 - May 2023 Tranche B pre-funded exchange warrants 92,801 - October 2023 pre-funded warrants 289,726 - Total 16,492,132 8,397,088 The following potentially dilutive securities outstanding have been excluded from the computations of diluted weighted-average shares outstanding because such securities have an antidilutive impact due to losses reported (in common stock equivalent shares): As of December 31, 2023 2022 Warrants issued to 2010/2012 convertible note 6,804 6,804 Warrants issued to underwriter to purchase common 1,100 1,100 2018 PIPE warrants - 34,241 March 2022 common warrants 1,929,066 4,000,000 May 2023 Tranche B warrants 6,750,000 - Options to purchase common stock 2,369,665 686,574 Outstanding restricted stock units 15,534 19,068 Total 11,072,169 4,747,787 |
Defined Contribution Plan
Defined Contribution Plan | 12 Months Ended |
Dec. 31, 2023 | |
Retirement Benefits [Abstract] | |
Defined Contribution Plan | Note 12. Defined Contribution Plan The Company sponsors a 401(k) Plan, which stipulates that eligible employees can elect to contribute to the 401(k) Plan, subject to certain limitations of eligible compensation. The Company may match employee contributions in amounts to be determined at the Company’s sole discretion. The Company made no matching contributions during the years ended December 31, 2023 and 2022. |
Subsequent Events
Subsequent Events | 12 Months Ended |
Dec. 31, 2023 | |
Subsequent Events [Abstract] | |
Subsequent Events | Note 13. Subsequent Events On February 8, 2024, the Company entered into a six-month office license agreement to license 4,141 square feet of additional space adjacent to its existing office where the Company is currently located in Redwood City, California. The term of the new space expires October 31, 2024 , unless terminated earlier in accordance with the license agreement. |
Basis of Presentation and Sum_2
Basis of Presentation and Summary of Significant Accounting Policies (Policies) | 12 Months Ended |
Dec. 31, 2023 | |
Accounting Policies [Abstract] | |
Basis of Presentation | Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP), and the applicable rules and regulations of the Securities and Exchange Commission (SEC). Certain reclassifications on the consolidated statements of cash flows have been made to conform to current period presentation. The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. |
Reverse Stock Split | Reverse Stock Split On June 1, 2022, the stockholders of the Company approved a reverse stock split of its common stock at a ratio of one-for-fifteen , to be effected at the sole discretion of the Company’s Board of Directors as described in the proxy statement filed with the SEC on April 21, 2022. The implementation of the reverse stock split was approved by the Company’s Board of Directors on August 16, 2022. On August 26, 2022, the Company filed a certificate of amendment to its amended and restated certificate of incorporation in order to effectuate a reverse stock split of the Company’s issued and outstanding common stock on a one-for-fifteen basis. All common share and per share data are retrospectively restated to give effect of the split for all periods presented herein. After giving eff ect to the reverse stock split, the total number of shares of all classes of capital stock that the Corporation is authorized to issue is 110,000,000 shares, consisting of 100,000,000 shares of common stock, having a par value of $ 0.001 and 10,000,000 shares of preferred stock, having a par value of $ 0.001 . |
Use of Estimates | Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities, and reported amounts of expenses in the financial statements and accompanying notes. Actual results could differ from those estimates. Key estimates in the financial statements include the valuation of deferred income tax assets, the valuation of financial instruments, stock-based compensation, accrued costs for services rendered in connection with third-party contractor clinical trial activities, and the valuation of contingent liabilities for the purchase price of assets obtained through acquisition. |
Concentration of Credit Risk | Concentration of Credit Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents at U.S. banking institutions. At December 31, 2023, the majority of the Company’s funds were invested with two separate financial institutions and at times these balances may exceed the federally-insured limits. Operating cash in excess of federally-insured limits is custodied at a separate financial institution with an overnight sweep feature into a U.S. government money market fund. As of December 31, 2022, the Company’s funds were invested in one financial institution which at times may exceed the federally insured limit. |
Segments | Segments The Company operates in one segment. Management uses one measurement of profitability and does not segregate its business for internal reporting, making operating decisions, and assessing financial performance. All long-lived assets are maintained in the U.S. |
Cash and Cash Equivalents | Cash and Cash Equivalents The Company considers all highly liquid investments, including its money market funds, purchased with an original maturity of three months or less to be cash equivalents. The Company’s cash and cash equivalents are held primarily in institutions in the U.S. and include deposits in a money market funds which were unrestricted as to withdrawal or use. |
Prepaid Expenses and Other Current Assets | Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consist of payments primarily related to clinical trials, insurance and short-term deposits. Prepaid expenses are initially recorded upon payment and are expensed as goods or services are received. |
Property and Equipment, Net | Property and Equipment, Net Property and equipment are stated at cost net of accumulated depreciation and amortization calculated using the straight-line method over the estimated useful lives of the assets, generally between three and five years . Leasehold improvements are amortized on a straight-line basis over the lesser of their useful life or the remaining term of the lease. Maintenance and repairs are charged to expense as incurred, and improvements are capitalized. When assets are retired or otherwise disposed of, the cost and accumulated depreciation are removed from the balance sheet and any resulting gain or loss is reflected in operations in the period realized. |
Leases | Leases The Company determines whether an arrangement is a lease at inception. Specifically, it considers whether it controls the underlying asset and has the right to obtain substantially all the economic benefits or outputs from the asset. If the contractual arrangement contains a lease, the Company then determines whether it is an operating or finance lease. Right-of-Use (ROU) assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at commencement date based on the present value of lease payments over the lease term. Lease expense for operating lease payments is recognized on a straight-line basis over the lease term. Finance lease classification results in a front-loaded expense recognition pattern over the lease term as it recognizes interest expense and amortization expense as separate components of lease expense. The Company does not separate lease components from non-lease components for all classes of underlying assets, and instead accounts for the lease and non-lease components as a single component. Variable lease payments are recognized as they are incurred and primarily include common area maintenance, utilities, real estate taxes, insurance and other operating costs that are passed on from the lessor in proportion to the space leased by the Company. The Company does not recognize lease assets and lease liabilities for leases with an original lease term of less than one year. |
Long-Lived Assets | Long-Lived Assets The Company reviews its long-lived assets for impairment annually and whenever events or changes in circumstances indicate that the carrying amount of the assets may not be fully recoverable. The Company evaluates assets for potential impairment by comparing estimated future undiscounted net cash flows to the carrying amount of the asset. If the carrying amount of the assets exceeds the estimated future undiscounted cash flows, impairment is measured based on the difference between the carrying amount and the fair value of the assets. |
Intangible Assets | Intangible Assets In March 2017, the Company completed the acquisition of Essentialis in accordance with the merger agreement by and between the Company and Essentialis dated December 22, 2016 (the “Merger Agreement”). The merger transaction was accounted for as an asset acquisition under the acquisition method of accounting and accordingly, the value of $ 22.0 million was assigned to the identifiable intangible asset relating to the patent for DCCR, which patent expires in June 2028. Intangible assets with finite lives are amortized on a straight-line basis over their estimated useful lives, which for the patent is 11 years . The useful life of the intangible asset is evaluated each reporting period to determine whether events and circumstances warrant a revision to the remaining useful life. |
Research and Development | Research and Development Research and development costs are charged to operations as incurred. Research and development costs consist primarily of salaries, benefits, bonus, share-based compensation, consultant fees, certain facility costs and other costs associated with clinical trials. Clinical trial costs are a significant component of research and development expenses and include costs associated with third-party contractors and other vendors. Invoicing from third-party contractors for services performed can often occur several months later. The Company accrues the costs incurred for clinical trial activities as measured by patient progression and the timing of various aspects of the trial. For other services the Company accrues the costs in connection with third-party contractor activities based on its estimate of fees and costs associate with the contract that were rendered during the period and they are expensed as incurred. Costs to acquire technologies to be used in research and development that have not reached technological feasibility and have no alternative future use are expensed to research and development costs when incurred. |
Change in Fair Value of Contingent Consideration | Change in fair value of contingent consideration The Company recorded the value of contingent future consideration to be paid for the acquisition of Essentialis as a liability in March 2017 at the date of the acquisition. The changes in value of the liability for the contingent consideration since the acquisition date are recorded as operating expense in the consolidated statements of operations. |
Income Taxes | Income Taxes The Company accounts for income taxes using the asset and liability method. Under this method, deferred income tax assets and liabilities are recorded based on the estimated future tax effects of differences between the amounts at which assets and liabilities are recorded for financial reporting purposes and the amounts recorded for income tax purposes. A valuation allowance is provided against the Company’s deferred income tax assets when their realization is not reasonably assured. The Company assesses all material positions taken in any income tax return, including all significant uncertain positions, in all tax years that are still subject to assessment or challenge by relevant taxing authorities. Assessing an uncertain tax position begins with the initial determination of the position’s sustainability and is measured at the largest amount of benefit that is greater than fifty percent likely of being realized upon ultimate settlement. As of each balance sheet date, unresolved uncertain tax positions must be reassessed, and the Company will determine whether (i) the factors underlying the sustainability assertion have changed and (ii) the amount of the recognized tax benefit is still appropriate. The recognition and measurement of tax benefits requires significant judgment. Judgments concerning the recognition and measurement of a tax benefit might change as new information becomes available. |
Common Stock Purchase Warrants and Other Derivative Financial Instruments | Common Stock Purchase Warrants and Other Derivative Financial Instruments The Company classifies common stock purchase warrants and other free standing derivative financial instruments as equity if the contracts (i) require physical settlement or net-share settlement or (ii) give the Company a choice of net-cash settlement or settlement in its own shares (physical settlement or net-share settlement). The Company classifies any contracts that (i) require net-cash settlement (including a requirement to net cash settle the contract if an event occurs and if that event is outside the control of the Company), (ii) give the counterparty a choice of net-cash settlement or settlement in shares (physical settlement or net-share settlement), or (iii) contain reset provisions as either an asset or a liability. The Company assesses classification of its freestanding derivatives at each reporting date to determine whether a change in classification between equity and liabilities is required. The Company determined that certain freestanding derivatives, which principally consist of 2018 PIPE Warrants, do not satisfy the criteria for classification as equity instruments due to the existence of certain cash settlement features that are not within the sole control of the Company or variable settlement provision that cause them to not be indexed to the Company’s own stock. The Company classified the 2018 PIPE Warrants at their fair value and re-measured them at each balance sheet date until they were exercised or expired. Any changes in the fair value were recognized as Other income (expense) in the consolidated statements of operations. The 2018 PIPE Warrants expired in December 2023. |
Stock-Based Compensation | Stock-Based Compensation Stock-based compensation costs related to stock options and restricted stock units granted to employees, nonemployees and directors are measured at the date of grant based on the estimated fair value of the award. For restricted stock units this fair value is based on the Company’s common stock price on the grant date. The Company estimates the grant date fair value of stock options, and the resulting stock-based compensation expense, using the Black-Scholes option-pricing model. The grant date fair value of stock-based awards is recognized on a straight-line basis over the requisite service period, which is generally the vesting period for service-based awards. For performance-based awards the requisite service period is the longest explicit, implicit or derived service period based on management’s estimate of the probability of the performance criteria being satisfied, adjusted at each balance sheet date. The Black-Scholes option-pricing model requires the use of highly subjective assumptions to estimate the fair value of stock-based awards. If the Company had made different assumptions, its stock-based compensation expense, net loss and net loss per share of common stock could have been significantly different. These assumptions include: • Expected volatility: We calculated the estimated volatility rate for stock options granted based on the volatility of our common stock for a historical period equal to the expected life of the stock options. • Expected life: Due to the lack of historical exercise history, the expected life of the Company’s service-based stock options is determined utilizing the “simplified method”, based on the average of the contractual term of the options and the weighted-average vesting period. The expected life for performance-based options is determined based on consideration of the contractual term of the stock options, an estimate of the date the performance criteria would be met and expectations of employee behavior. • Risk-free rate: The risk-free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected time to liquidity. • Expected divided yield: The Company has never declared or paid any cash dividends and does not presently plan to pay cash dividends in the foreseeable future. Consequently, it used an expected dividend yield of zero . The Company accounts for forfeitures as they occur. |
Recent Adopted Accounting Pronouncements | Recent Adopted Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (FASB) or other standard setting bodies that are adopted by the Company as of the specified effective date . In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures, which amends the guidance in ASC 740, Income Taxes. This ASU is intended to improve the transparency of income tax disclosures by requiring (1) consistent categories and greater disaggregation of information in the rate reconciliation and (2) income taxes paid disaggregated by jurisdiction. It also includes certain other amendments to improve the effectiveness of income tax disclosures. This ASU is effective for fiscal years beginning after December 15, 2024. Adoption is permitted either prospectively or retrospectively, and the Company will adopt this ASU on a prospective basis. The Company is currently evaluating the impact of adopting this ASU on its consolidated financial statements and disclosures. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses of Financial Instruments, which, together with subsequent amendments, amends the requirement on the measurement and recognition of expected credit losses for financial assets held. ASU 2016-13 is effective for the Company for the annual periods beginning after December 15, 2022, including interim periods within those fiscal years, with early adoption permitted. The Company adopted this ASU effective January 1, 2023 . There was no impact on the Company's financial statements upon the adoption of this ASU. Other accounting standards that have been issued or proposed by FASB or other standards-setting bodies that do not require adoption until a future date are not currently expected to have a material impact on the Company’s financial statements upon adoption. |
Fair Value of Financial Instr_2
Fair Value of Financial Instruments (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Fair Value Disclosures [Abstract] | |
Summary of Financial Instruments Measured at Fair Value on Recurring Basis | The following table sets forth the Company’s financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands): Fair Value Measurements at December 31, 2023 Total Level 1 Level 2 Level 3 Liabilities Essentialis purchase price contingency liability $ 11,549 $ - $ - $ 11,549 Fair Value Measurements at December 31, 2022 Total Level 1 Level 2 Level 3 Liabilities 2018 PIPE Warrant liability $ 1 $ — $ — $ 1 Essentialis purchase price contingency liability 8,835 — — 8,835 Total common stock warrant and contingent $ 8,836 $ — $ — $ 8,836 |
Summary of Changes in Fair Value of Level 3 Financial Instruments | The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 assets and liabilities (dollars in thousands): 2018 PIPE Warrants Purchase Price Number of Contingent Warrants Liability Liability Balance at December 31, 2021 34,241 $ 31 $ 9,547 Change in value of 2018 PIPE Warrants — ( 30 ) - Change in value of contingent liability — — ( 712 ) Balance at December 31, 2022 34,241 $ 1 $ 8,835 Change in value of 2018 PIPE Warrants — 419 — Exercise of 2018 PIPE Warrants ( 21,789 ) ( 183 ) — Expiration of 2018 PIPE Warrants ( 12,452 ) ( 237 ) — Change in value of contingent liability — — 2,714 Balance at December 31, 2023 0 $ - $ 11,549 |
Other Financial Statement Det_2
Other Financial Statement Details (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Other Financial Statement Details Disclosure [Abstract] | |
Schedule of Property and Equipment | Property and equipment are summarized in the following table (in thousands): December 31, December 31, Computer hardware $ 72 $ 72 Furniture and fixtures 29 29 101 101 Less accumulated depreciation and amortization ( 89 ) ( 75 ) Total $ 12 $ 26 |
Schedule of Intangible Assets | Intangible assets consist of the following (in thousands): December 31, 2023 December 31, 2022 Amount Accumulated Net Amount Accumulated Net Patents and merger costs $ 22,003 $ ( 13,254 ) $ 8,749 $ 22,003 $ ( 11,310 ) $ 10,693 |
Schedule of Future Amortization Expense | Future amortization expense for intangible assets over their remaining useful lives is as follows (in thousands): Year ending December 31 Patents and 2024 1,944 2025 1,944 2026 1,944 2027 1,944 2028 and thereafter 973 Total $ 8,749 |
Warrants (Tables)
Warrants (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Text Block [Abstract] | |
Fair Value of Convertible Preferred Stock Warrant Liability | The following summarizes certain key assumptions used in estimating the fair values: December 31, Volatility 117 % Contractual term (years) 1.0 Expected dividend yield — % Risk-free rate 4.74 % |
Leases (Tables)
Leases (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Leases [Abstract] | |
Schedule of Components of Lease Expense | The components of lease expense were as follows (in thousands): Year Ended December 31, December 31, Operating lease cost: Operating lease cost $ 312 $ 324 Short-term lease cost 44 29 Total operating lease cost $ 356 $ 353 |
Schedule Of Supplemental Cash Flow Information Related To Leases | Supplemental cash flow information related to leases was as follows (in thousands): Year Ended December 31, December 31, Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 341 $ 354 |
Operating Lease Liability Maturity | The following is a schedule by year of future maturities of the Company’s operating lease liabilities as of December 31, 2023 (in thousands): 2024 287 2025 143 Total lease payments 430 Less interest ( 27 ) Total $ 403 |
Stockholders' Equity (Tables)
Stockholders' Equity (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Equity [Abstract] | |
Summary of Outstanding Common Stock Warrants | As of December 31, 2023 and December 31, 2022, the following table summarizes the Company's outstanding common stock warrants: As of December 31, 2023 As of December 31, 2022 Number of Common Warrant Shares Weighted Average Exercise Price per Share Number of Common Warrant Shares Weighted Average Exercise Price per Share Expiration Date Common stock warrants 7,904 $ 388.94 7,904 $ 388.94 November 2024 2018 PIPE warrants — $ - 34,241 $ 30.00 December 2023 March 2022 Common warrants 1,929,066 $ 4.50 4,000,000 $ 4.50 March 2027 March 2022 Pre-funded warrants — $ - 1,280,965 $ 0.15 March 2027 May 2023 Tranche A Pre-funded warrants 2,758,281 $ 0.01 — $ — November 2026 May 2023 Tranche B warrants 6,750,000 $ 2.50 — $ — November 2026 (1) May 2023 Tranche B Pre-funded warrants 451,632 $ 0.01 — $ — November 2026 October 2023 Pre-funded warrants 1,175,000 $ 0.01 — $ — N/A Total 13,071,883 5,323,110 (1) Subject to earlier expiration as described above. |
Summary of Stock Based Compensation Expense | Stock compensation expense was recognized in the consolidated statements of operations as follows (in thousands): Year ended December 31, December 31, Research and development $ 2,434 $ 692 General and administrative 3,511 1,838 Total $ 5,945 $ 2,530 |
Schedule of Fair Value of Award Granted Using Black-Scholes Option Pricing Model | The fair value of each award granted was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions: Year Ended December 31, December 31, Expected life (years) 5.3 - 6.1 5.5 - 6.0 Risk-free interest rate 3.5 %- 4.5 % 1.7 %- 3.1 % Volatility 98 %- 122 % 88 %- 95 % Dividend rate — % — % |
Summary of Stock Option and Restricted Stock Unit Transactions | The following table summarizes stock option transactions for the years ended December 31, 2023 and 2022 as issued under the 2014 Plan and the Inducement Plan: Number of Weighted- Weighted Aggregate Intrinsic Value Outstanding Share (in years) (in thousands) Balance at December 31, 2021 408,329 $ 46.28 7.94 Options granted 283,919 3.56 Options canceled/forfeited ( 5,674 ) 19.31 Balance at December 31, 2022 686,574 $ 28.83 7.93 Options granted 1,821,784 6.18 Options exercised ( 89,993 ) 4.01 Options canceled/forfeited ( 48,700 ) 67.84 Balance at December 31, 2023 2,369,665 $ 11.56 8.72 $ 70,834 Options exercisable at December 31, 2023 797,988 $ 18.31 7.76 $ 20,320 Options vested and expected to vest at 2,346,707 $ 11.34 8.75 $ 70,834 |
Summary of Restricted Stock Unit Transactions | The following table summarizes restricted stock unit transactions for the years ended December 31, 2023 and 2022 as issued under the 2014 Plan: Number of Weighted- Outstanding at December 31, 2021 29,050 $ 57.75 Restricted stock units granted 8,965 5.33 Restricted stock units vested ( 18,646 ) 32.55 Restricted stock units cancelled/forfeited ( 301 ) 57.85 Outstanding at December 31, 2022 19,068 $ 57.75 Restricted stock units granted 420,710 5.49 Restricted stock units vested ( 423,248 ) 6.43 Restricted stock units cancelled/forfeited ( 996 ) 5.25 Outstanding at December 31, 2023 15,534 $ 43.92 |
Income Taxes (Tables)
Income Taxes (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Income Tax Disclosure [Abstract] | |
Schedule of Geographical Distribution of Loss before Income Taxes | The geographical distribution of loss before income taxes are summarized below (in thousands): December 31, 2023 2022 United States $ ( 39,180 ) $ ( 24,173 ) Foreign 192 106 Loss before income taxes $ ( 38,988 ) $ ( 24,067 ) |
Provision for Income Tax Benefit by Applying Statutory Federal Income Tax Rate to Operating Loss | The provision for income tax benefit differs from the amount estimated by applying the statutory federal income tax rate to the operating loss due to the following (in thousands): December 31, 2023 2022 Tax (benefit) on the loss before income tax expense $ ( 8,187 ) $ ( 5,055 ) State tax (benefit) at statutory rate, net of federal ( 505 ) ( 527 ) Foreign rate differential 6 - Change in valuation allowance 8,934 5,702 Change in research and development credits ( 1,631 ) ( 652 ) Stock based compensation ( 600 ) ( 734 ) Change in fair value of warrants 38 ( 6 ) Change in fair value of contingent consideration 570 ( 150 ) Section 162(m) limitation 589 - Change in net operating loss true up 39 739 Change in capital losses — 405 Change in state rates 653 375 Other 94 ( 97 ) Provision for income tax benefit $ — $ — |
Significant Components of Company's Deferred Tax Assets and Liabilities | Significant components of the Company’s deferred tax assets and liabilities are as follows at December 31, 2023 and 2022 (in thousands): December 31, 2023 2022 Non-current deferred tax assets: Federal and state net operating loss carryforwards $ 51,481 $ 49,024 Research and other credits 6,352 4,146 Capitalized research and development 6,778 2,828 Reserves and accruals 655 547 Fixed assets 29 44 Capital loss carryover 432 555 Stock based compensation 2,013 2,682 Lease liability 85 42 Other deferred tax assets 54 72 Gross non-current deferred tax assets 67,879 59,940 Intangible assets ( 1,837 ) ( 2,888 ) Right-of-use assets ( 86 ) ( 35 ) Total non-current deferred tax liabilities ( 1,923 ) ( 2,923 ) Total deferred tax assets 65,956 57,017 Valuation allowance ( 65,956 ) ( 57,017 ) Net deferred tax assets $ — $ — |
Summary of Gross Unrecognized Tax Benefits | The following tables summarize the activities of gross unrecognized tax benefits (in thousands): December 31, 2023 2022 Beginning balance $ 1,936 $ 1,557 Increase related to current year tax positions 1,002 379 Ending balance $ 2,938 $ 1,936 |
Net Loss per Share (Tables)
Net Loss per Share (Tables) | 12 Months Ended |
Dec. 31, 2023 | |
Earnings Per Share [Abstract] | |
Schedule of Weighted-Average Common Shares Outstanding | The following securities are included in the weighted-average common shares outstanding used to calculate basic and diluted net loss per common share: As of December 31, 2023 2022 Common stock 15,040,036 7,409,165 March 2022 pre-funded warrants 290,665 987,923 May 2023 Tranche A pre-funded exchange warrants 778,904 - May 2023 Tranche B pre-funded exchange warrants 92,801 - October 2023 pre-funded warrants 289,726 - Total 16,492,132 8,397,088 |
Schedule of Potentially Dilutive Securities Outstanding Excluded from Computations of Diluted Weighted-Average Shares Outstanding | The following potentially dilutive securities outstanding have been excluded from the computations of diluted weighted-average shares outstanding because such securities have an antidilutive impact due to losses reported (in common stock equivalent shares): As of December 31, 2023 2022 Warrants issued to 2010/2012 convertible note 6,804 6,804 Warrants issued to underwriter to purchase common 1,100 1,100 2018 PIPE warrants - 34,241 March 2022 common warrants 1,929,066 4,000,000 May 2023 Tranche B warrants 6,750,000 - Options to purchase common stock 2,369,665 686,574 Outstanding restricted stock units 15,534 19,068 Total 11,072,169 4,747,787 |
Liquidity - Additional Informat
Liquidity - Additional Information (Detail) - USD ($) | 1 Months Ended | 12 Months Ended | ||
Oct. 02, 2023 | May 31, 2023 | Dec. 31, 2023 | Dec. 31, 2022 | |
Cash And Cash Equivalents [Line Items] | ||||
Net loss | $ (38,988,000) | $ (24,067,000) | ||
Accumulated deficit | (276,410,000) | (237,422,000) | ||
Cash and cash equivalents | 169,681,000 | 14,602,000 | ||
Net cash used in operating activities | (24,940,000) | (20,781,000) | ||
Proceeds from issuance or sale of equity | $ 129,000,000 | 129,000,000 | ||
Securities Purchase Agreement [Member] | ||||
Cash And Cash Equivalents [Line Items] | ||||
Sale and issuance of warrants | $ 10,000,000 | |||
Tranche A [Member] | ||||
Cash And Cash Equivalents [Line Items] | ||||
Proceeds from warrant exercise | 15,000,000 | |||
Tranche B [Member] | ||||
Cash And Cash Equivalents [Line Items] | ||||
Contingent receipt upon exerise of warrants and future performance of company | 16,900,000 | |||
Proceeds from warrant exercise | 18,100,000 | |||
Underwritten Public Offering [Member] | ||||
Cash And Cash Equivalents [Line Items] | ||||
Proceeds from warrant exercise | 0 | |||
Underwritten Public Offering [Member] | Securities Purchase Agreement [Member] | Maximum [Member] | ||||
Cash And Cash Equivalents [Line Items] | ||||
Proceeds from sale of common stock, net of costs | $ 60,000,000 | |||
March 2022 Warrants [Member] | ||||
Cash And Cash Equivalents [Line Items] | ||||
Proceeds from warrant exercise | $ 9,300,000 |
Basis of Presentation and Sum_3
Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail) $ / shares in Units, $ in Millions | 12 Months Ended | |||
Aug. 26, 2022 $ / shares shares | Jun. 01, 2022 | Dec. 31, 2023 USD ($) Segment $ / shares shares | Dec. 31, 2022 $ / shares shares | |
Schedule Of Significant Accounting Policies [Line Items] | ||||
Number of operating segments | Segment | 1 | |||
Estimated useful life | 11 years | |||
Reverse stock split ratio | 0.0666 | 0.0666 | ||
Reverse stock split | one-for-fifteen | |||
Capital stock, shares authorized | 110,000,000 | |||
Common stock, shares authorized | 100,000,000 | 100,000,000 | 100,000,000 | |
Common stock, par value (in dollars per share) | $ / shares | $ 0.001 | $ 0.001 | $ 0.001 | |
Preferred stock, shares authorized | 10,000,000 | 10,000,000 | 10,000,000 | |
Preferred stock, par value | $ / shares | $ 0.001 | $ 0.001 | $ 0.001 | |
Essentialis, Inc. [Member] | ||||
Schedule Of Significant Accounting Policies [Line Items] | ||||
Net intangible assets acquired | $ | $ 22 | |||
Minimum [Member] | ||||
Schedule Of Significant Accounting Policies [Line Items] | ||||
Estimated useful lives of property and equipment | 3 years | |||
Maximum [Member] | ||||
Schedule Of Significant Accounting Policies [Line Items] | ||||
Estimated useful lives of property and equipment | 5 years | |||
ASU No. 2016-13 [Member] | ||||
Schedule Of Significant Accounting Policies [Line Items] | ||||
Change in Accounting Principle, Accounting Standards Update, Adoption Date | Jan. 01, 2023 | |||
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false] | true | |||
Change in Accounting Principle, Accounting Standards Update, Adopted [true false] | true |
Fair Value of Financial Instr_3
Fair Value of Financial Instruments - Summary of Financial Instruments Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022 |
Liabilities | ||
Contingent liability for Essentialis purchase price | $ 11,549 | $ 8,835 |
2018 PIPE Warrant Liability [Member] | ||
Liabilities | ||
Warrant liability | 0 | 1 |
Fair Value, Measurements, Recurring [Member] | ||
Liabilities | ||
Total common stock warrant and contingent consideration liability | 8,836 | |
Fair Value, Measurements, Recurring [Member] | Derivative Financial Instruments, Liabilities [Member] | 2018 PIPE Warrant Liability [Member] | ||
Liabilities | ||
Warrant liability | 1 | |
Essentialis, Inc. [Member] | Fair Value, Measurements, Recurring [Member] | ||
Liabilities | ||
Contingent liability for Essentialis purchase price | 11,549 | 8,835 |
Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | ||
Liabilities | ||
Total common stock warrant and contingent consideration liability | 8,836 | |
Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Derivative Financial Instruments, Liabilities [Member] | 2018 PIPE Warrant Liability [Member] | ||
Liabilities | ||
Warrant liability | 1 | |
Level 3 [Member] | Essentialis, Inc. [Member] | Fair Value, Measurements, Recurring [Member] | ||
Liabilities | ||
Contingent liability for Essentialis purchase price | $ 11,549 | $ 8,835 |
Fair Value of Financial Instr_4
Fair Value of Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2023 | Dec. 31, 2022 | Mar. 07, 2017 | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | |||
Milestones payment | $ 100 | $ 200 | |
Percentage of probability of achieving milestone | 88% | 72% | |
Essentialis, Inc. [Member] | |||
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | |||
Maximum potential cash earnout payments | $ 21.2 |
Fair Value of Financial Instr_5
Fair Value of Financial Instruments - Summary of Changes in Fair Value of Level 3 Financial Instruments (Detail) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | ||
Balance at the beginning of period, in shares | 5,323,110 | |
Balance at the end of period, in shares | 13,071,883 | 5,323,110 |
Purchase price contingent liability [Member] | ||
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | ||
Balance at the beginning of period | $ 8,835 | $ 9,547 |
Change in value of liabilities | 2,714 | (712) |
Balance at end of period | $ 11,549 | $ 8,835 |
2018 PIPE Warrant Liability [Member] | ||
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | ||
Balance at the beginning of period, in shares | 34,241 | |
Exercise of warrants, shares | 21,789 | |
Balance at the end of period, in shares | 12,452 | 34,241 |
2018 PIPE Warrant Liability [Member] | Common stock warrant liability [Member] | ||
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | ||
Balance at the beginning of period | $ 1 | $ 31 |
Balance at the beginning of period, in shares | 34,241 | 34,241 |
Change in value of liabilities | $ 419 | $ (30) |
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] | Fair Value Adjustment of Warrants | Fair Value Adjustment of Warrants |
Exercise of warrants, shares | (21,789) | |
Exercise of warrants | $ (183) | |
Expiration of warrants, in shares | (12,452) | |
Expiration of warrants | $ (237) | |
Balance at end of period | $ 0 | $ 1 |
Balance at the end of period, in shares | 0 | 34,241 |
Other Financial Statement Det_3
Other Financial Statement Details - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022 |
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | $ 101 | $ 101 |
Less accumulated depreciation and amortization | (89) | (75) |
Total | 12 | 26 |
Computer Hardware [Member] | ||
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | 72 | 72 |
Furniture and Fixtures [Member] | ||
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | $ 29 | $ 29 |
Other Financial Statement Det_4
Other Financial Statement Details - Additional Information (Detail) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Other Financial Statement Details Disclosure [Abstract] | ||
Depreciation expense | $ 14 | $ 20 |
Amortization | $ 1,900 | $ 1,900 |
Other Financial Statements Deta
Other Financial Statements Details - Intangible Assets (Detail) - Patents and Merger Costs [Member] - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022 |
Finite Lived Intangible Assets [Line Items] | ||
Amount | $ 22,003 | $ 22,003 |
Accumulated Amortization | (13,254) | (11,310) |
Net Amount | $ 8,749 | $ 10,693 |
Other Financial Statement Det_5
Other Financial Statement Details - Future Amortization Expense (Detail) - Patents And Trademark [Member] $ in Thousands | Dec. 31, 2023 USD ($) |
Finite Lived Intangible Assets [Line Items] | |
2024 | $ 1,944 |
2025 | 1,944 |
2026 | 1,944 |
2027 | 1,944 |
2028 and thereafter | 973 |
Net Amount | $ 8,749 |
Warrants - Additional Informati
Warrants - Additional Information (Detail) | 12 Months Ended | |||
Dec. 31, 2023 USD ($) shares | Dec. 31, 2022 USD ($) $ / shares shares | Aug. 26, 2022 shares | Dec. 19, 2018 $ / shares shares | |
Class Of Warrant Or Right [Line Items] | ||||
Change in fair value of common stock warrants | $ | $ 182,000 | $ (30,000) | ||
Issuance of common stock | 100,000,000 | 100,000,000 | 100,000,000 | |
Number of Common Warrant Shares | 13,071,883 | 5,323,110 | ||
Expected Dividend Yield [Member] | ||||
Class Of Warrant Or Right [Line Items] | ||||
Measurement input | 0 | |||
2018 PIPE Warrant Liability [Member] | ||||
Class Of Warrant Or Right [Line Items] | ||||
Number of common stock purchased upon issuance of warrants | 34,241 | |||
Exercise price of warrants (in dollars per share) | $ / shares | $ 30 | $ 30 | ||
Warrant issuance description | The 2018 PIPE Warrants were issued on December 19, 2018 in the 2018 PIPE Offering, pursuant to a Warrant Agreement with each of the investors in the 2018 PIPE Offering, and prior to their expiration on December 21, 2023, entitled the holders to purchase 34,241 shares of the Company’s common stock at an exercise price equal to $30.00 per share, subject to adjustments. | |||
Change in fair value of common stock warrants | $ | $ 200,000 | $ (30,000) | ||
Estimated warrants outstanding | $ | $ 0 | $ 1,000 | ||
Exercise of warrants, shares | 21,789 | |||
Issuance of common stock | 9,683 | |||
Proceeds from warrant exercise | $ | $ 200,000 | |||
Number of Common Warrant Shares | 12,452 | 34,241 |
Warrants - Fair Value of Conver
Warrants - Fair Value of Convertible Preferred Stock Warrant Liability (Detail) - 2018 PIPE Warrant Liability [Member] | Dec. 31, 2022 |
Volatility [Member] | |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] | |
Measurement input | 1.17 |
Contractual Term [Member] | |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] | |
Measurement term | 1 year |
Risk-free Rate [Member] | |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] | |
Measurement input | 0.0474 |
Leases - Additional Information
Leases - Additional Information (Detail) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Lessee Lease Description [Line Items] | ||
Operating lease, extension expiration | 2025-05 | |
Operating Lease, Liability, Current | $ 273 | $ 155 |
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] | Operating Lease, Liability, Current | Operating Lease, Liability, Current |
Long-term lease liabilities | $ 130 | $ 0 |
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] | Long-term lease liabilities | Long-term lease liabilities |
Increase in right of use assets | $ 600 | |
Increase in lease liability | $ 600 | |
Operating lease remaining term | 17 months | 5 months |
Operating lease, weighted average discount rate | 8.25% | 9% |
Redwood City, California [Member] | ||
Lessee Lease Description [Line Items] | ||
Operating lease, description | began in June 2021 and expired in May 2023 | |
Operating lease, term of contract | 24 months | |
Operating lease beginning date | 2021-06 | |
Operating lease, expiration | 2023-05 |
Leases - Schedule of Components
Leases - Schedule of Components of Lease Expense (Detail) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Leases [Abstract] | ||
Operating lease cost | $ 312 | $ 324 |
Short-term lease cost | 44 | 29 |
Total operating lease cost | $ 356 | $ 353 |
Leases - Schedule of Supplement
Leases - Schedule of Supplemental Cash Flow Information Related to Leases (Detail) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Cash paid for amounts included in the measurement of lease liabilities: | ||
Operating cash flows from operating leases | $ 341 | $ 354 |
Leases - Schedule of Future Mat
Leases - Schedule of Future Maturities (Detail) $ in Thousands | Dec. 31, 2023 USD ($) |
Leases [Abstract] | |
2024 | $ 287 |
2025 | 143 |
Total lease payments | 430 |
Less interest | (27) |
Total | $ 403 |
Stockholders' Equity - Addition
Stockholders' Equity - Additional Information (Detail) - USD ($) | 1 Months Ended | 12 Months Ended | ||||||||||
Oct. 02, 2023 | Sep. 26, 2023 | Dec. 16, 2022 | Oct. 31, 2023 | Mar. 31, 2022 | Dec. 31, 2023 | Dec. 31, 2022 | May 25, 2023 | Mar. 23, 2023 | Feb. 17, 2023 | Aug. 26, 2022 | Jul. 31, 2021 | |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Convertible preferred stock, shares authorized | 10,000,000 | 10,000,000 | 10,000,000 | |||||||||
Number of Common Warrant Shares | 13,071,883 | 5,323,110 | ||||||||||
Public offering price per pre-funded warrant | $ 19.99 | |||||||||||
Proceeds from issuance or sale of equity | $ 129,000,000 | $ 129,000,000 | ||||||||||
Offering costs | $ 8,200,000 | |||||||||||
Stock-based compensation expense | $ 5,945,000 | $ 2,530,000 | ||||||||||
Expected dividend yield | 0% | 0% | ||||||||||
Weighted average grant date fair value per option granted (in dollars per share) | $ 5.04 | $ 2.62 | ||||||||||
Number of shares available for issuance under the plan on the first day of each year | 31,678,159 | 8,159,382 | ||||||||||
Minimum [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Ownership interest of voting rights of all classes of stock (percent) | 10% | |||||||||||
2020 Inducement Equity Incentive Plan [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Number of shares available for grant | 445,668 | 500,000 | ||||||||||
Stock Options [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Income tax benefits recognized from stock-based compensation | $ 1,900,000 | $ 0 | ||||||||||
Number of options granted | 1,821,784 | 283,919 | ||||||||||
Expected dividend yield | 0% | |||||||||||
Future stock-based compensation for unvested employee options granted and outstanding | $ 9,100,000 | |||||||||||
Future stock-based compensation, requisite service period | 2 years 6 months | |||||||||||
Stock Options [Member] | 2014 Equity Incentive Plan [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Number of shares available for grant | 1,465 | 1,800,000 | 238,329 | |||||||||
Stock Options [Member] | 2014 Equity Incentive Plan [Member] | Minimum [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Percentage of fair market value | 110% | |||||||||||
Stock Options [Member] | 2014 Equity Incentive Plan [Member] | Maximum [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Contractual term of option | 10 years | |||||||||||
ISOs [Member] | 2014 Equity Incentive Plan [Member] | Maximum [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Contractual term of option | 5 years | |||||||||||
Restricted Stock Units [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Unrecognized stock based compensation expense | $ 200,000 | |||||||||||
Stock units granted | 420,710 | 8,965 | ||||||||||
Shares granted to date | 414,710 | |||||||||||
Vesting percentage | 100% | |||||||||||
Fair value of restricted stock units vested | $ 12,000,000 | $ 100,000 | ||||||||||
Weighted average grant-date fair value of all restricted stock units granted | $ 5.49 | $ 5.33 | ||||||||||
Weighted average remaining vesting period | 2 months 12 days | |||||||||||
Restricted Stock Units [Member] | 2014 Equity Incentive Plan [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Stock units granted | 420,710 | 8,965 | ||||||||||
Weighted average grant-date fair value of all restricted stock units granted | $ 5.49 | $ 5.33 | ||||||||||
Warrants to Purchase Stock [Member] | 2010 and 2012 Convertible Promissory Notes [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Number of Common Warrant Shares | 6,804 | |||||||||||
Weighted Average Exercise Price per Share | $ 365.25 | |||||||||||
Expiration period | 2024-11 | |||||||||||
Underwriter [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Number of Common Warrant Shares | 1,100 | |||||||||||
Weighted Average Exercise Price per Share | $ 535.5 | |||||||||||
Warrants term | 10 years | |||||||||||
Expiration period | 2024-11 | |||||||||||
March 2022 Common Warrants [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Number of Common Warrant Shares | 1,929,066 | 4,000,000 | ||||||||||
Weighted Average Exercise Price per Share | $ 4.5 | $ 4.5 | ||||||||||
Expiration period | 2027-03 | |||||||||||
Controlled Equity Offering Sales Agreement [Member] | Cantor [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Issuance of common stock (shares) | 1,877,170 | |||||||||||
Common stock, maximum aggregate purchase price | $ 25,000,000 | |||||||||||
Net proceeds from sale of common stock | $ 7,400,000 | |||||||||||
Securities Purchase Agreement [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Sale and issuance of warrants to purchase common stock | 10,000,000 | |||||||||||
Number of common stock purchased upon issuance of warrants | 22,598,870 | |||||||||||
Weighted Average Exercise Price per Share | $ 0.4425 | |||||||||||
Proceeds from sale of common stock and pre-funded warrants | $ 60,000,000 | |||||||||||
Shares issued from sale of common stock | 1,825,000 | |||||||||||
Shares issued from sale of pre-funded warrants | 1,175,000 | |||||||||||
Tranche A [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Number of Common Warrant Shares | 8,598,870 | |||||||||||
Warrants and rights immediately exercisable term | 30 days | |||||||||||
Proceeds from warrant exercise | 15,000,000 | |||||||||||
Sale and issuance of warrants to purchase common stock | $ 15,000,000 | |||||||||||
Weighted Average Exercise Price per Share | $ 1.75 | |||||||||||
Exercisable warrants maximum aggregate exercise price | $ 15,000,000 | |||||||||||
Tranche B [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Number of Common Warrant Shares | 14,000,000 | |||||||||||
Warrants expire term prior to anniversary date of issuance | 3 years 6 months | |||||||||||
Warrants and rights exercisable term from following receipt of U.S. Food and drug administration approval | 30 days | |||||||||||
Proceeds from warrant exercise | 18,100,000 | |||||||||||
Contingent receipt upon exerise of warrants and future performance of company | 16,900,000 | |||||||||||
Weighted Average Exercise Price per Share | $ 2.5 | |||||||||||
Exercisable warrants maximum aggregate exercise price | $ 35,000,000 | |||||||||||
Public Offering [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Price per unit | $ 20 | |||||||||||
Underwritten Public Offering [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Issuance of common stock (shares) | 3,450,000 | 2,666,667 | ||||||||||
Price per unit | $ 20 | $ 3.75 | ||||||||||
Proceeds from warrant exercise | $ 0 | |||||||||||
Warrants exercised | 1,280,965 | |||||||||||
Number of common stock purchased upon issuance of warrants | 1,333,333 | |||||||||||
Public offering price per pre-funded warrant | $ 3.6 | |||||||||||
Per share exercise price for pre-funded warrant | $ 0.15 | |||||||||||
Measurement term | 5 years | |||||||||||
Weighted Average Exercise Price per Share | $ 4.5 | |||||||||||
Proceeds from offering after deducting underwriting discount and other estimated offering expenses | $ 69,000,000 | $ 13,800,000 | ||||||||||
Underwritten Public Offering [Member] | March 2022 Common Warrants [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Proceeds from warrant exercise | $ 9,300,000 | |||||||||||
Warrants exercised | 2,070,934 | |||||||||||
Underwritten Public Offering [Member] | Securities Purchase Agreement [Member] | Maximum [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Net proceeds from sale of common stock | $ 60,000,000 | |||||||||||
Employee Stock Purchase Plan [Member] | ||||||||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||||||||||
Number of shares available for grant | 1,864 | |||||||||||
Percentage of outstanding stock maximum | 1% | |||||||||||
Number of shares available for issuance under the plan on the first day of each year | 3,729 | |||||||||||
Number of shares purchases by employees | 0 |
Stockholders' Equity - Summary
Stockholders' Equity - Summary of Outstanding Common Stock Warrants (Detail) - $ / shares | 12 Months Ended | ||
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 19, 2018 | |
Class of Warrant or Right [Line Items] | |||
Number of Common Shares | 13,071,883 | 5,323,110 | |
Common Stock Warrants [Member] | |||
Class of Warrant or Right [Line Items] | |||
Number of Common Shares | 7,904 | 7,904 | |
Weighted Average Exercise Price per Share | $ 388.94 | $ 388.94 | |
Expiration Date | 2024-11 | ||
2018 PIPE Warrants [Member] | |||
Class of Warrant or Right [Line Items] | |||
Number of Common Shares | 12,452 | 34,241 | |
Weighted Average Exercise Price per Share | $ 30 | $ 30 | |
Expiration Date | 2023-12 | ||
March 2022 Common Warrants [Member] | |||
Class of Warrant or Right [Line Items] | |||
Number of Common Shares | 1,929,066 | 4,000,000 | |
Weighted Average Exercise Price per Share | $ 4.5 | $ 4.5 | |
Expiration Date | 2027-03 | ||
March 2022 Pre-funded Warrants [Member] | |||
Class of Warrant or Right [Line Items] | |||
Number of Common Shares | 1,280,965 | ||
Weighted Average Exercise Price per Share | $ 0.15 | ||
Expiration Date | 2027-03 | ||
May 2023 Tranche A Pre-funded Warrants [Member] | |||
Class of Warrant or Right [Line Items] | |||
Number of Common Shares | 2,758,281 | ||
Weighted Average Exercise Price per Share | $ 0.01 | ||
Expiration Date | 2026-11 | ||
May 2023 Tranche B Warrants [Member] | |||
Class of Warrant or Right [Line Items] | |||
Number of Common Shares | 6,750,000 | ||
Weighted Average Exercise Price per Share | $ 2.5 | ||
Expiration Date | 2026-11 | ||
May 2023 Tranche B Pre-funded Warrants [Member] | |||
Class of Warrant or Right [Line Items] | |||
Number of Common Shares | 451,632 | ||
Weighted Average Exercise Price per Share | $ 0.01 | ||
Expiration Date | 2026-11 | ||
October 2023 Pre-funded Warrants [Member] | |||
Class of Warrant or Right [Line Items] | |||
Number of Common Shares | 1,175,000 | ||
Weighted Average Exercise Price per Share | $ 0.01 |
Stockholders' Equity - Summar_2
Stockholders' Equity - Summary of Stock Based Compensation Expense (Detail) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||
Stock-based compensation expense | $ 5,945 | $ 2,530 |
Research and Development [Member] | ||
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||
Stock-based compensation expense | 2,434 | 692 |
General and Administrative [Member] | ||
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||
Stock-based compensation expense | $ 3,511 | $ 1,838 |
Stockholders' Equity - Schedule
Stockholders' Equity - Schedule of Fair Value of Award Granted Using Black-Scholes Option Pricing Model (Detail) | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
Dividend rate | 0% | 0% |
Minimum [Member] | ||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
Expected life (years) | 5 years 3 months 18 days | 5 years 6 months |
Risk-free interest rate | 3.50% | 1.70% |
Volatility | 98% | 88% |
Maximum [Member] | ||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
Expected life (years) | 6 years 1 month 6 days | 6 years |
Risk-free interest rate | 4.50% | 3.10% |
Volatility | 122% | 95% |
Stockholders' Equity - Summar_3
Stockholders' Equity - Summary of Stock Option and Restricted Stock Unit Transactions (Detail) - Stock Options [Member] - USD ($) $ / shares in Units, $ in Thousands | 12 Months Ended | ||
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] | |||
Options granted | 1,821,784 | 283,919 | |
2014 Plan and Inducement Plan [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] | |||
Beginning balance | 686,574 | 408,329 | |
Options granted | 1,821,784 | 283,919 | |
Options exercised | (89,993) | ||
Options canceled/forfeited | (48,700) | (5,674) | |
Ending balance | 2,369,665 | 686,574 | 408,329 |
Options exercisable at end of period (shares) | 797,988 | ||
Options vested and expected to vest at end of period (shares) | 2,346,707 | ||
Weighted-Average Exercise Price per Share | |||
Beginning balance (in dollars per share) | $ 28.83 | $ 46.28 | |
Options granted (in dollars per share) | 6.18 | 3.56 | |
Options exercised (in dollars per share) | 4.01 | ||
Options canceled/forfeited (in dollars per share) | 67.84 | 19.31 | |
Ending balance (in dollars per share) | 11.56 | $ 28.83 | $ 46.28 |
Options exercisable at end of period (in dollars per share) | 18.31 | ||
Options vested and expected to vest at end of period (in dollars per share) | $ 11.34 | ||
Weighted Average Remaining Contractual Term | |||
Options outstanding at end of period | 8 years 8 months 19 days | 7 years 11 months 4 days | 7 years 11 months 8 days |
Options exercisable at end of period | 7 years 9 months 3 days | ||
Options vested and expected to vest at end of period | 8 years 9 months | ||
Options outstanding at end of period | $ 70,834 | ||
Options exercisable at end of period | 20,320 | ||
Options vested and expected to vest at end of period | $ 70,834 |
Stockholders' Equity - Summar_4
Stockholders' Equity - Summary of Restricted Stock Unit Transactions (Detail) - Restricted Stock Units [Member] - $ / shares | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] | ||
Restricted stock units granted | 420,710 | 8,965 |
Weighted-average grant date fair value | ||
Restricted stock units granted (in dollars per share) | $ 5.49 | $ 5.33 |
2014 Equity Incentive Plan [Member] | ||
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] | ||
Beginning balance | 19,068 | 29,050 |
Restricted stock units granted | 420,710 | 8,965 |
Restricted stock units vested | (423,248) | (18,646) |
Restricted stock units cancelled/forfeited | (996) | (301) |
Ending balance | 15,534 | 19,068 |
Weighted-average grant date fair value | ||
Beginning balance (in dollars per share) | $ 57.75 | $ 57.75 |
Restricted stock units granted (in dollars per share) | 5.49 | 5.33 |
Restricted stock units vested (in dollars per share) | 6.43 | 32.55 |
Restricted stock units cancelled/forfeited (in dollars per share) | 5.25 | 57.85 |
Ending balance (in dollars per share) | $ 43.92 | $ 57.75 |
Income Taxes - Schedule of Geog
Income Taxes - Schedule of Geographical Distribution of Loss before Income Taxes (Detail) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Income Tax Disclosure [Abstract] | ||
United States | $ (39,180) | $ (24,173) |
Foreign | 192 | 106 |
Loss before income taxes | $ (38,988) | $ (24,067) |
Income Taxes - Provision for In
Income Taxes - Provision for Income Tax Benefit by Applying Statutory Federal Income Tax Rate to Operating Loss (Detail) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract] | ||
Tax (benefit) on the loss before income tax expense computed at the federal statutory rate | $ (8,187) | $ (5,055) |
State tax (benefit) at statutory rate, net of federal benefit | (505) | (527) |
Foreign rate differential | 6 | |
Change in valuation allowance | 8,934 | 5,702 |
Change in research and development credits | (1,631) | (652) |
Stock based compensation | (600) | (734) |
Change in fair value of warrants | 38 | (6) |
Change in fair value of contingent consideration | 570 | (150) |
Section 162(m) limitation | 589 | |
Change in net operating loss true up | 39 | 739 |
Change in capital losses | 405 | |
Change in state rates | 653 | 375 |
Other | $ 94 | $ (97) |
Income Taxes - Significant Comp
Income Taxes - Significant Components of Company's Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022 |
Non-current deferred tax assets: | ||
Federal and state net operating loss carryforwards | $ 51,481 | $ 49,024 |
Research and other credits | 6,352 | 4,146 |
Capitalized research and development | 6,778 | 2,828 |
Reserves and accruals | 655 | 547 |
Fixed assets | 29 | 44 |
Capital loss carryover | 432 | 555 |
Stock based compensation | 2,013 | 2,682 |
Lease liability | 85 | 42 |
Other deferred tax assets | 54 | 72 |
Gross non-current deferred tax assets | 67,879 | 59,940 |
Intangible assets | (1,837) | (2,888) |
Right-of-use assets | (86) | (35) |
Total non-current deferred tax liabilities | (1,923) | (2,923) |
Total deferred tax assets | 65,956 | 57,017 |
Valuation allowance | $ (65,956) | $ (57,017) |
Income Taxes - Additional Infor
Income Taxes - Additional Information (Detail) - USD ($) | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Income Tax Contingency [Line Items] | ||
Increase (decrease) in valuation allowance | $ 8,900,000 | |
Unrecognized assets and liabilities related to uncertain tax positions | 2,900,000 | |
Unrecognized tax benefits that would impact effective tax rate | 0 | $ 0 |
Unrecognized tax benefit offset by change in valuation allowance | 2,900,000 | |
Internal Revenue Service (IRS) [Member] | ||
Income Tax Contingency [Line Items] | ||
Operating loss carryforwards | $ 500,000 | |
Minimum [Member] | ||
Income Tax Contingency [Line Items] | ||
Research and development costs, amortization period | 5 years | |
Maximum [Member] | ||
Income Tax Contingency [Line Items] | ||
Research and development costs, amortization period | 15 years | |
U.S. Federal Jurisdiction [Member] | ||
Income Tax Contingency [Line Items] | ||
Operating loss carryforwards | $ 206,700,000 | |
Operating loss carryforwards, carried forward indefinitely | 93,100,000 | |
U.S. Federal Jurisdiction [Member] | Research Tax Credit Carryforward [Member] | ||
Income Tax Contingency [Line Items] | ||
Tax credit carryforwards | 6,400,000 | |
State Tax Jurisdiction [Member] | ||
Income Tax Contingency [Line Items] | ||
Operating loss carryforwards | 111,000,000 | |
State Tax Jurisdiction [Member] | Research Tax Credit Carryforward [Member] | ||
Income Tax Contingency [Line Items] | ||
Tax credit carryforwards | 3,400,000 | |
Foreign Tax Authority [Member] | Her Majesty's Revenue and Customs (HMRC) [Member] | ||
Income Tax Contingency [Line Items] | ||
Operating loss carryforwards | $ 2,300,000 |
Income Taxes - Summary of Gross
Income Taxes - Summary of Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] | ||
Beginning balance | $ 1,936 | $ 1,557 |
Increase related to current year tax positions | 1,002 | 379 |
Ending balance | $ 2,938 | $ 1,936 |
Net Loss per Share - Schedule o
Net Loss per Share - Schedule of Weighted-Average Common Shares Outstanding (Detail) - shares | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Class of Stock [Line Items] | ||
Weighted-average common shares outstanding used to calculate basic shares | 16,492,132 | 8,397,088 |
Weighted-average common shares outstanding used to calculate diluted shares | 16,492,132 | 8,397,088 |
Common Stock [Member] | ||
Class of Stock [Line Items] | ||
Weighted-average common shares outstanding used to calculate basic shares | 15,040,036 | 7,409,165 |
Weighted-average common shares outstanding used to calculate diluted shares | 15,040,036 | 7,409,165 |
March 2022 Pre-funded Warrants [Member] | ||
Class of Stock [Line Items] | ||
Weighted-average common shares outstanding used to calculate basic shares | 290,665 | 987,923 |
Weighted-average common shares outstanding used to calculate diluted shares | 290,665 | 987,923 |
May 2023 Tranche A Pre-funded Exchange Warrants [Member] | ||
Class of Stock [Line Items] | ||
Weighted-average common shares outstanding used to calculate basic shares | 778,904 | |
Weighted-average common shares outstanding used to calculate diluted shares | 778,904 | |
May 2023 Tranche B Pre-funded Exchange Warrants [Member] | ||
Class of Stock [Line Items] | ||
Weighted-average common shares outstanding used to calculate basic shares | 92,801 | |
Weighted-average common shares outstanding used to calculate diluted shares | 92,801 | |
October 2023 Pre-funded Warrants [Member] | ||
Class of Stock [Line Items] | ||
Weighted-average common shares outstanding used to calculate basic shares | 289,726 | |
Weighted-average common shares outstanding used to calculate diluted shares | 289,726 |
Net Loss per Share - Schedule_2
Net Loss per Share - Schedule of Potentially Dilutive Securities Outstanding Excluded from Computations of Diluted Weighted-Average Shares Outstanding (Detail) - shares | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
Antidilutive securities excluded from computations of diluted weighted-average shares outstanding | 11,072,169 | 4,747,787 |
Warrants Issued to 2010/2012 Convertible Note Holders to Purchase Common Stock [Member] | ||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
Antidilutive securities excluded from computations of diluted weighted-average shares outstanding | 6,804 | 6,804 |
Options to Purchase Common Stock [Member] | ||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
Antidilutive securities excluded from computations of diluted weighted-average shares outstanding | 2,369,665 | 686,574 |
Outstanding Restricted Stock Units [Member] | ||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
Antidilutive securities excluded from computations of diluted weighted-average shares outstanding | 15,534 | 19,068 |
Warrants Issued to Underwriter to Purchase Common Stock [Member] | ||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
Antidilutive securities excluded from computations of diluted weighted-average shares outstanding | 1,100 | 1,100 |
2018 PIPE Warrants [Member] | ||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
Antidilutive securities excluded from computations of diluted weighted-average shares outstanding | 34,241 | |
March 2022 Common Warrants [Member] | ||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
Antidilutive securities excluded from computations of diluted weighted-average shares outstanding | 1,929,066 | 4,000,000 |
May 2023 Tranche B Warrants [Member] | ||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
Antidilutive securities excluded from computations of diluted weighted-average shares outstanding | 6,750,000 |
Defined Contribution Plan - Add
Defined Contribution Plan - Additional Information (Detail) - USD ($) | 12 Months Ended | |
Dec. 31, 2023 | Dec. 31, 2022 | |
Retirement Benefits [Abstract] | ||
Matching contribution by Company | $ 0 | $ 0 |
Subsequent Events - Additional
Subsequent Events - Additional Information (Detail) - Redwood City, California [Member] - ft² | Feb. 08, 2024 | Dec. 31, 2023 |
Subsequent Event [Line Items] | ||
Operating lease, term of contract | 24 months | |
Subsequent Event [Member] | ||
Subsequent Event [Line Items] | ||
Operating lease, term of contract | 6 months | |
Area of operating lease | 4,141 | |
Operating lease, expiration date | Oct. 31, 2024 |