Summary of Significant Accounting Policies | 2. Summary of Significant Accounting Policies Basis of Presentation The unaudited interim financial statements have been prepared in accordance with United States generally accepted accounting principles (“U.S. GAAP”). The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts and disclosures reported in the financial statements and accompanying notes. The interim balance sheet as of September 30, 2024, the statements of operations and comprehensive loss, statements of stockholders’ equity for the three and nine months ended September 30, 2024 and 2023 and statements of cash flows for the nine months ended September 30, 2024 and 2023 are unaudited. The unaudited interim financial statements have been prepared on the same basis as the audited annual financial statements and reflect, in the opinion of management, all adjustments of a normal and recurring nature that are necessary for the fair presentation of the Company’s financial position as of September 30, 2024 and its results of operations and comprehensive loss for the three and nine months ended September 30, 2024 and 2023 and its cash flows for the nine months ended September 30, 2024 and 2023. Certain information and note disclosures normally included in annual audited financial statements prepared in accordance with U.S. GAAP have been omitted. The financial data and the other financial information disclosed in these notes to the interim financial statements are also unaudited. The results of operations for any interim period are not necessarily indicative of the results to be expected for the entire year or for any other future annual or interim period. These interim financial statements should be read in conjunction with the Company’s audited financial statements included in the Company’s Annual Report on Form 10-K, which was filed with the U.S. Securities and Exchange Commission (“SEC”) on March 14, 2024. Use of Estimates Management uses significant judgment when making estimates related to common stock valuation and related stock-based compensation expense, accrued research and development expense, valuation of long-lived assets and lease-related assets and liabilities. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ from those estimates under different assumptions or conditions, and those differences could be material to the financial position and results of operations. Concentration of Credit Risk and Other Risks and Uncertainties Financial instruments that potentially subject the Company to credit risk principally consist of cash, cash equivalents and investments. These financial instruments are currently held in accounts in varying amounts at four separate financial institutions that management believes possess high credit quality. Amounts on deposit with these financial institutions have and will continue to exceed federally-insured limits. The Company has not experienced any losses on its cash deposits. Additionally, the Company’s investment policy limits its investments to certain types of securities issued by or backed by the U.S. government and its agencies. The Company is subject to a number of risks similar to that of other early stage biopharmaceutical companies, including, but not limited to, the need to obtain adequate additional funding, possible failure of current or future clinical trials, its reliance on third-parties to conduct its clinical trials, the need to obtain regulatory and marketing approvals for its product candidates, competitive developments, the need to successfully commercialize and gain market acceptance of the Company’s product candidates, protection of proprietary technology, and the need to secure and maintain adequate manufacturing arrangements with third-parties. If the Company does not successfully commercialize or partner its product candidates, it will be unable to generate product revenue or achieve profitability. Cash, Cash Equivalents and Restricted Cash The Company considers all highly liquid investments with original maturities of three months or less from the date of purchase to be cash equivalents. The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the Company’s balance sheets and which, in aggregate, represent the amounts reported in the accompanying statements of cash flows (in thousands): September 30, December 31, 2024 2023 Cash and cash equivalents $ 10,449 $ 66,440 Restricted cash in other long-term assets 1,472 1,472 Total $ 11,921 $ 67,912 September 30, December 31, 2023 2022 Cash and cash equivalents $ 70,519 $ 87,217 Restricted cash in other long-term assets 1,472 1,472 Total $ 71,991 $ 88,689 Restricted cash at September 30, 2024 represents $ 1.5 million in security deposits for the lease of the Company’s facility in San Carlos, California. The security deposit is in the form of a letter of credit secured by restricted cash and is recorded in other long-term assets on the Company’s balance sheets . Investments The Company invests in marketable securities, primarily securities issued by the U.S. government and its agencies. The Company’s investments are considered available-for-sale and are classified as current assets even when the stated maturities of the underlying securities exceed one year from the date of the current balance sheet being reported. This classification reflects management’s ability and intent to utilize proceeds from the sale of such investments to fund ongoing operations. Unrealized gains and losses are excluded from earnings and are reported as a component of accumulated other comprehensive gain (loss) unless the decline in fair value of the investments is attributable to expected credit losses and if it is more likely than not that the Company will be required or will intend to sell the investment before recovery of its amortized cost basis. The cost of securities sold is determined using the specific-identification method. Interest earned and adjustments for the amortization of premiums and discounts on investments are included in interest income on the statements of operations and comprehensive loss. Realized gains and losses on the sale of investments are included in other expense, net, on the statements of operations and comprehensive loss. Valuation of Long-lived Assets Long-lived assets, including property and equipment and finite-lived intangible assets, are reviewed for possible impairment whenever events or circumstances indicate that the carrying amount of such assets may not be recoverable. The evaluation is performed at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities. Recoverability of these assets is measured by a comparison of the carrying amounts to the future undiscounted cash flows the assets are expected to generate from the use and eventual disposition. If such review indicates that the carrying amount of the long-lived assets is not recoverable, the carrying amount of such assets is reduced to fair value. The Company has recorded impairment charges during the nine months ended September 30, 2024. For a further description of the impairment, see Note 5 – Impairment of Long-Lived Assets in the accompanying notes. Operating Leases The Company accounts for its leases in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 842, “Leases” (“ASC 842”). Right-of-use assets represent the Company’s right to use an underlying asset over the lease term and include any lease payments made prior to the lease commencement date and are reduced by lease incentives. Lease liabilities represent the present value of the total lease payments over the lease term, calculated using the Company’s incremental borrowing rate. In determining the Company’s incremental borrowing rate, consideration is given to the term of the lease and the Company’s credit risk. The Company recognizes options to extend a lease when it is reasonably certain that it will exercise such extension. The Company does not recognize options to terminate a lease when it is reasonably certain that it will not exercise such early termination options. Lease expense is recognized on a straight-line basis over the expected lease term. Accrued Research and Development Expense Service agreements with contract development and manufacturing organizations (“CDMOs”), clinical contract research organizations (“CROs”) and clinical investigative sites comprise a significant component of the Company’s research and development activities. External costs for these vendors are recognized as the services are incurred. The Company accrues for expenses resulting from obligations under agreements with its third-parties for which the timing of payments does not match the periods over which the materials or services are provided to the Company. Accruals are recorded based on estimates of services received and efforts expended pursuant to agreements established with CDMOs, clinical CROs, clinical investigative sites and other outside service providers. These estimates are typically based on contracted amounts applied to the proportion of work performed and determined through analysis with internal personnel and external service providers as to the progress or stage of completion of the services. The Company makes judgements and estimates in determining the accrual balance in each reporting period. In the event advance payments are made to a CDMO, clinical CRO, clinical investigative site or other outside service provider, the payments are recorded within prepaid expenses and other current assets or other long-term assets, as appropriate, and subsequently recognized as research and development expense when the associated services have been performed. As actual costs become known, the Company adjusts its liabilities and assets. Inputs, such as the extent of services received and the duration of services to be performed, may vary from the Company’s estimates, which will result in adjustments to research and development expense in future periods. Changes in these estimates that result in material changes to the Company’s accruals could materially affect the Company’s results of operations. The Company’s historical estimates have not been materially different from actual amounts recorded. Research and Development Expense Research and development costs are expensed as incurred. Research and development costs include, among others, consulting costs, salaries, benefits, travel, stock-based compensation, laboratory supplies and other non-capital equipment utilized for in-house research, allocation of facilities and overhead costs and external costs paid to third-parties that conduct research and development activities on the Company’s behalf. Costs to terminate commitments with third-party suppliers performing research and development activities and amounts incurred in connection with license agreements, including milestone payments, are also included in research and development expense. Advance payments for goods or services to be rendered in the future for use in research and development activities are deferred and included in prepaid expenses and other current assets or other long-term assets, as appropriate. The deferred amounts are expensed as the related goods are delivered or the services are performed. Comprehensive Loss Comprehensive loss is defined as the change in stockholders’ equity during a period from transactions and other events and circumstances from non-owner sources. The differences between net loss and comprehensive loss for the three and nine months ended September 30, 2024 and 2023 are a result of unrealized gains and losses on the Company’s investments in marketable securities included in current assets on the Company’s balance sheets. Net Loss per Share The Company calculates basic net loss per share by dividing the net loss attributable to common stockholders by the weighted-average shares of common stock outstanding during the period. The Company calculates diluted net loss per share after giving consideration to all potentially dilutive securities outstanding during the period using the treasury-stock and if-converted methods, except where the effect of including such securities would be anti-dilutive. Because the Company has reported net losses since inception, the effect from potentially dilutive securities would have been anti-dilutive and therefore has been excluded from the calculation of diluted net loss per share. Basic and diluted net loss per share was calculated as follows (in thousands, except per share data): Three Months Ended Nine Months Ended September 30, September 30, 2024 2023 2024 2023 Numerator: Net loss $ ( 18,372 ) $ ( 45,626 ) $ ( 116,194 ) $ ( 123,150 ) Denominator: Weighted-average shares of common stock outstanding, 89,024 87,115 88,571 86,539 Net loss per share, basic and diluted $ ( 0.21 ) $ ( 0.52 ) $ ( 1.31 ) $ ( 1.42 ) The following table sets forth the potentially dilutive securities that have been excluded from the calculation of diluted net loss per share due to their anti-dilutive effect for the periods indicated (in thousands): Nine Months Ended September 30, 2024 2023 Options to purchase common stock 13,214 7,966 Unvested restricted stock units 5,714 5,902 Unvested performance stock units — 2,851 Shares issuable under employee stock purchase plans 69 58 Total 18,997 16,777 Recently Issued and Adopted Accounting Pronouncements In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. This ASU requires entities to expand their existing income tax disclosures, specifically related to the rate reconciliation and income taxes paid. This authoritative guidance will be effective for us in fiscal year 2025, with early adoption permitted. The Company is currently evaluating the impact of the ASU, but does not expect any material impact upon adoption. In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which requires all public entities, including public entities with a single reportable segment, to provide in interim and annual periods one or more measures of segment profit or loss used by the chief operating decision maker to allocate resources and assess performance. Additionally, the standard requires disclosures of significant segment expenses and other segment items as well as incremental qualitative disclosures. The guidance in this update is effective for the Company’s fiscal year 2024 annual reporting period. The Company is currently in the process of evaluating the effects of this pronouncement on its related disclosures. |