Summary of Significant Accounting Policies (Policies)	12 Months Ended
Dec. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation—The Company’s consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). 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.
Use of Estimates	Use of Estimates—The preparation of financial statements in conformity with U.S. GAAP requires management to make judgements, estimates and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses, and related disclosures. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances. These estimates form the basis for making judgments about the carrying values of assets and liabilities when these values are not readily apparent from other sources. Accounting estimates and judgements are inherently uncertain, and the actual results could differ from these estimates.
March 2024 Reverse Stock Split	March 2024 Reverse Stock Split—On March 21, 2024, the Company effected a 1-for-10 reverse stock split of its common stock. The par value and the authorized shares of the common stock were not adjusted as a result of the reverse stock split. All equity related information including per share amounts for all periods presented in these consolidated financial statements and the notes thereto have been adjusted retroactively, where applicable, to reflect this reverse stock split.
Foreign Currency	Foreign Currency—Assets and liabilities of non-U.S. subsidiaries that operate in a local currency environment, where the local currency is the functional currency, are translated to U.S. dollars at exchange rates in effect at the balance sheet date, with the resulting translation adjustments directly recorded to a separate component of accumulated other comprehensive loss. Upon sale or upon complete or substantially complete liquidation of an investment in a foreign entity, the amount attributable to that entity and accumulated in the translation adjustment component of equity is removed from the separate component of equity and reported as part of the gain or loss on sale or liquidation of the investment for the period during which the sale or liquidation occurs. Income and expense accounts are translated at average exchange rates for the period. Transactions which are not in the functional currency of the entity are remeasured into the functional currency and gains or losses resulting from the remeasurement recorded in other income, net.
Cash and Cash Equivalents	Cash and Cash Equivalents—The Company considers all highly liquid investments purchased with original maturities of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents include cash held in banks, money market accounts and highly liquid debt securities. Cash equivalents are stated at fair value.
Restricted Cash	Restricted Cash—Restricted cash primarily consists of cash collateral to letter of credit provided to the landlord in relation to a lease agreement. See Note 6, Leases for additional information.
Short-Term Investments	Short-Term Investments—All short-term investments in debt securities have been classified as “available for sale” and are carried at fair value. Unrealized gains and losses, net of any related tax effects, are excluded from earnings and are included in other comprehensive loss and reported as a separate component of stockholders’ equity until realized. The cost of securities sold is based on the specific-identification method. The amortized cost of securities is adjusted for amortization of premiums and accretion of discounts to maturity. Interest on short-term investments is included in other income, net in the Company’s consolidated statements of operations and comprehensive loss. In accordance with the Company’s investment policy, management invests to diversify credit risk and only invests in securities with high credit quality, including U.S. government securities. The Company assesses available-for-sale debt securities on a quarterly basis to see whether any unrealized loss is due to credit-related factors. Factors considered in determining whether an impairment is credit-related include the extent to which the investment’s fair value is less than its cost basis, declines in published credit ratings, changes in interest rates, and any other adverse factors related to the security. If it is determined that a credit-related impairment exists, the Company will measure the credit loss based on a discounted cash flow model. Credit-related impairments on available-for-sale debt securities are recognized as an allowance for credit losses with a corresponding adjustment to other income, net in the Company’s consolidated statement of operations. The unrealized loss position that is not credit-related is recorded, net of any related tax effects, in other comprehensive income until realized. There were no credit-related losses recognized for the periods presented.
Accrued Interest Receivable	Accrued Interest Receivable—Accrued interest receivable related to the Company’s available-for-sale debt securities is presented within prepaid expenses and other current assets on the Company’s consolidated balance sheets. The Company has elected to exclude accrued interest receivable from both the fair value and the amortized cost basis of available-for-sale debt securities for the purposes of identifying and measuring any impairment. The Company writes off accrued interest receivable once it has determined that the asset is not realizable. Any write offs of accrued interest receivable are recorded by reversing interest income, recognizing credit loss expense, or a combination of both. To date, the Company has not written off any accrued interest receivables associated with its available-for-sale debt securities.
Segment Reporting	Segment Reporting—The Company operates and manages its business as one reporting and operating segment, which is the business of developing and commercializing gene therapeutics. The Company’s chief executive officer, who is the chief operating decision maker (“CODM”), assesses segment performance and decides how to allocate resources based on total operating expenses as reported on the consolidated statements of operations and comprehensive loss. See Note 11, Segment Reporting, for additional information.
Concentrations of Credit Risk and Other Uncertainties	Concentrations of Credit Risk and Other Uncertainties—Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents and short-term investments. Risks associated with cash, cash equivalents, short-term investments are mitigated by the Company’s investment policy, which limits the Company’s investing to securities having specified credit ratings. Management believes that the Company is not exposed to significant credit risk. The Company is subject to certain risks and uncertainties, including, but not limited to changes in any of the following areas that the Company believes could have a material adverse effect on future financial position or results of operations: the ability to obtain future financing; regulatory approval and market acceptance of, and reimbursement for, the Company’s product candidates; performance of third-party clinical research organizations and manufacturers; development of sales channels; protection of intellectual property; litigation or claims against the Company based on intellectual property, patent, product, regulatory or other factors; and the Company’s ability to attract and retain employees necessary to support growth.
Property and Equipment	Property and Equipment—Property and equipment are recorded at cost, net of accumulated depreciation and amortization. Depreciation is recorded using the straight-line method over the estimated useful lives of the assets, generally three to five years. Leasehold improvements are capitalized and amortized over the shorter period of their expected lives or the lease term. Major replacements and improvements are capitalized, while general repairs and maintenance are expensed as incurred.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets—Long-lived assets, including property and equipment and finite-lived intangible assets, are reviewed for impairment whenever facts or circumstances either internally or externally may indicate that the carrying value of an asset may not be recoverable. If there is an indication of impairment, the Company tests for recoverability by comparing the estimated undiscounted future cash flows expected to result from the use of the asset to the carrying amount of the asset or asset group. If the asset or asset group is determined to be impaired, any excess of the carrying value of the asset or asset group over its estimated fair value is recognized as an impairment loss.
Leases	Leases — For long-term operating leases, the Company recognizes a right-of-use asset and a lease liability on the Company's consolidated balance sheets. The Company determines if an arrangement contains a lease and the classification of the lease at inception. An arrangement contains a lease if there is an identified asset and if the Company controls the use of the identified asset throughout the period of use. The lease liability is determined as the present value of future lease payments and lease incentives over the expected lease term. Lease incentives are included in the measurement of the consideration in the contract at lease commencement when the Company is reasonably certain to incur costs to construct lessee assets. In order to determine the incremental borrowing rate, the Company determines its credit rating, adjusts the credit rating for the nature of the collateral, and benchmarks the borrowing rate against observable yields on comparable securities with a similar term. The incremental borrowing rate, the ROU asset and the lease liability are reevaluated upon a lease modification. It bases the ROU asset on the lease liability adjusted for any prepaid or deferred rent. The Company elected to combine lease and non-lease components for all underlying assets groups. The Company determines the lease term at the commencement date by considering whether renewal options and termination options are reasonably assured of exercise. For short term leases, the Company does not recognize a right-of-use asset and lease liability and recognizes the lease expense over the term of the lease on a straight-line basis. Rent expense for operating leases is recognized on a straight-line basis over the lease term and is included in operating expenses on the statements of operations and comprehensive loss. The variable lease payments primarily consist of common area maintenance and other operating costs. The Company assesses the probability of collecting lease payments under its sublease at each reporting date. The Company currently does not deem the collection of lease payments probable and therefore sublease income is constrained at the lesser of cash payments or straight-line sublease income. Sublease income/loss for operating leases is classified in general and administrative expenses based on payments collected and tenant improvement allowance disbursed to the subtenant.
Revenue Recognition	Revenue Recognition—The Company has primarily generated revenue through license, research and collaboration arrangements with its strategic partners. The Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the Company expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that the Company determines are within the scope of ASC 606, Revenue from Contracts with Customers, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies a performance obligation. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied.
Research and Development Expenses	Research and Development Expenses—Research and development expenses are charged to expense as incurred. Research and development expenses include primarily personnel-related costs, stock-based compensation expense, laboratory supplies, consulting costs, external contract research and development expenses, including expenses incurred under agreements with contract research organizations (“CROs”), the cost of acquiring, developing and manufacturing clinical trial materials, and overhead expenses, such as rent, equipment depreciation, insurance and utilities. Advance payments for goods or services for future research and development activities are deferred and expensed as the goods are delivered or the related services are performed. The Company estimates research and clinical trial expenses based on the services performed pursuant to contracts with research institutions and clinical research organizations that conduct and manage nonclinical studies and clinical trials on the Company’s behalf. In accruing service fees, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. These estimates are based on communications with the third-party service providers and the Company’s estimates of accrued expenses and on information available at each balance sheet date. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company adjusts the accrual accordingly.
Fair Value Measurements	Fair Value Measurements—Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. The carrying amounts of the Company’s financial instruments, including cash equivalents approximate their fair values due to their short-term maturities. See Note 4, Fair Value Measurements for the methodologies and assumptions used in valuing financial instruments.
Stock-based Compensation Expense	Stock-based Compensation Expense—Stock-based compensation expense related to stock awards to employees is measured at fair value of the award on the date of the grant. The Company estimates the grant-date fair value, and the resulting stock-based compensation expense, using the Black-Scholes valuation model for stock options and employee stock purchase and using intrinsic value, which is the closing price of its common stock on the date of the grant, for restricted stock units (“RSUs”) and performance stock units (“PSUs”). Expense recognition of PSU and performance-based options commences when the associated performance-based criteria are determined to be probable. The fair value of the award that is ultimately expected to vest is recognized as expense on a straight-line basis over the requisite service period, which is generally the vesting period. The Black-Scholes valuation model requires the use of following assumptions: Expected Term—The expected term assumption represents the period that the Company’s stock-based awards are expected to be outstanding and is determined using the simplified method. Expected Volatility—Expected volatility is based on the Company’s historical stock price volatility. Expected Dividend—The Black-Scholes valuation model calls for a single expected dividend yield as an input. The Company has never paid dividends and has no plans to pay dividends. Risk-Free Interest Rate—The risk-free interest rate is based on the U.S. Treasury zero-coupon issues in effect at the time of grant for periods corresponding with the expected term of option.
Income Taxes	Income Taxes—The Company accounts for income taxes using the asset and liability method. The Company records deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns. Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. In evaluating the ability to recover its deferred income tax assets, the Company considers all available positive and negative evidence, including its operating results, ongoing tax planning and forecasts of future taxable income on a jurisdiction-by-jurisdiction basis. In the event the Company determines that it would be able to realize its deferred income tax assets in the future in excess of their net recorded amount, it would make an adjustment to the valuation allowance that would reduce the provision for income taxes. Conversely, in the event that all or part of the net deferred tax assets are determined not to be realizable in the future, an adjustment to the valuation allowance would be charged to earnings in the period when such determination is made. As of December 31, 2024 and 2023, the Company has recorded a full valuation allowance on its deferred tax assets. Tax benefits related to uncertain tax positions are recognized when it is more likely than not that a tax position will be sustained upon examination. Interest and penalties related to unrecognized tax liabilities are included within the provision for income tax.
Comprehensive Loss	Comprehensive Loss—Comprehensive loss comprises net loss and other comprehensive loss. Other comprehensive loss consists of foreign currency translation adjustments and unrealized gain or loss on marketable securities.
Basic and Diluted Net Loss Per Share	Basic and Diluted Net Loss Per Share— Basic net loss per share is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding for the period. Diluted net loss per share is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period using the treasury stock method. Outstanding stock options, RSUs, and employee stock purchase plan (“ESPP”) are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive.
Recent Accounting Pronouncements and Recently Adopted Accounting Pronouncements	Recent Accounting Pronouncements In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (“ASU 2024-03”). ASU 2024-03 requires disaggregated disclosures of certain categories of expenses in the notes to the financial statements that are included in expense line items on the face of the income statement in annual and interim periods. ASU 2024-03 is effective for annual periods beginning after December 15, 2026 and interim periods beginning after December 15, 2027. The Company is evaluating the impact of this guidance on its financial statements and related disclosures. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (“ASU 2023-09”). ASU 2023-09 requires enhanced annual disclosures regarding the rate reconciliation and income taxes paid. ASU 2023-09 is effective for annual periods beginning after December 15, 2024 and may be adopted on a prospective or retrospective basis. Early adoption is permitted. The Company is evaluating the impact of this guidance on its financial statements and related disclosures. In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (“ASU 2023-07”). The amendments in ASU 2023-07 are intended to improve reportable segment disclosure, primarily through enhanced disclosures about significant segment expenses. ASU 2023-07 is effective for annual periods beginning after December 15, 2023, and interim periods beginning after December 15, 2024. The amendments in this ASU should be applied retrospectively to all prior periods presented in the financial statements. The Company retrospectively adopted ASU 2023-07 on December 31, 2024. The adoption of ASU 2023-07 did not have a material financial impact on the Company’s consolidated financial statements.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2024

Basis of Presentation and Principles of Consolidation

Basis of Presentation and Principles of Consolidation—The Company’s consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). 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.

Use of Estimates

Use of Estimates—The preparation of financial statements in conformity with U.S. GAAP requires management to make judgements, estimates and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses, and related disclosures. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances. These estimates form the basis for making judgments about the carrying values of assets and liabilities when these values are not readily apparent from other sources. Accounting estimates and judgements are inherently uncertain, and the actual results could differ from these estimates.

March 2024 Reverse Stock Split

March 2024 Reverse Stock Split—On March 21, 2024, the Company effected a 1-for-10 reverse stock split of its common stock. The par value and the authorized shares of the common stock were not adjusted as a result of the reverse stock split.

All equity related information including per share amounts for all periods presented in these consolidated financial statements and the notes thereto have been adjusted retroactively, where applicable, to reflect this reverse stock split.

Foreign Currency

Foreign Currency—Assets and liabilities of non-U.S. subsidiaries that operate in a local currency environment, where the local currency is the functional currency, are translated to U.S. dollars at exchange rates in effect at the balance sheet date, with the resulting translation adjustments directly recorded to a separate component of accumulated other comprehensive loss. Upon sale or upon complete or substantially complete liquidation of an investment in a foreign entity, the amount attributable to that entity and accumulated in the translation adjustment component of equity is removed from the separate component of equity and reported as part of the gain or loss on sale or liquidation of the investment for the period during which the sale or liquidation occurs. Income and expense accounts are translated at average exchange rates for the period. Transactions which are not in the functional currency of the entity are remeasured into the functional currency and gains or losses resulting from the remeasurement recorded in other income, net.

Cash and Cash Equivalents

Cash and Cash Equivalents—The Company considers all highly liquid investments purchased with original maturities of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents include cash held in banks, money market accounts and highly liquid debt securities. Cash equivalents are stated at fair value.

Restricted Cash

Restricted Cash—Restricted cash primarily consists of cash collateral to letter of credit provided to the landlord in relation to a lease agreement. See Note 6, Leases for additional information.

Short-Term Investments

Short-Term Investments—All short-term investments in debt securities have been classified as “available for sale” and are carried at fair value. Unrealized gains and losses, net of any related tax effects, are excluded from earnings and are included in other comprehensive loss and reported as a separate component of stockholders’ equity until realized. The cost of securities sold is based on the specific-identification method. The amortized cost of securities is adjusted for amortization of premiums and accretion of discounts to maturity. Interest on short-term investments is included in other income, net in the Company’s consolidated statements of operations and comprehensive loss. In accordance with the Company’s investment policy, management invests to diversify credit risk and only invests in securities with high credit quality, including U.S. government securities.

The Company assesses available-for-sale debt securities on a quarterly basis to see whether any unrealized loss is due to credit-related factors. Factors considered in determining whether an impairment is credit-related include the extent to which the investment’s fair value is less than its cost basis, declines in published credit ratings, changes in interest rates, and any other adverse factors related to the security. If it is determined that a credit-related impairment exists, the Company will measure the credit loss based on a discounted cash flow model. Credit-related impairments on available-for-sale debt securities are recognized as an allowance for credit losses with a corresponding adjustment to other income, net in the Company’s consolidated statement of operations. The unrealized loss position that is not credit-related is recorded, net of any related tax effects, in other comprehensive income until realized. There were no credit-related losses recognized for the periods presented.

Accrued Interest Receivable

Accrued Interest Receivable—Accrued interest receivable related to the Company’s available-for-sale debt securities is presented within prepaid expenses and other current assets on the Company’s consolidated balance sheets. The Company has elected to exclude accrued interest receivable from both the fair value and the amortized cost basis of available-for-sale debt securities for the purposes of identifying and measuring any impairment. The Company writes off accrued interest receivable once it has determined that the asset is not realizable. Any write offs of accrued interest receivable are recorded by reversing interest income, recognizing credit loss expense, or a combination of both. To date, the Company has not written off any accrued interest receivables associated with its available-for-sale debt securities.

Segment Reporting

Segment Reporting—The Company operates and manages its business as one reporting and operating segment, which is the business of developing and commercializing gene therapeutics. The Company’s chief executive officer, who is the chief operating decision maker (“CODM”), assesses segment performance and decides how to allocate resources based on total operating expenses as reported on the consolidated statements of operations and comprehensive loss. See Note 11, Segment Reporting, for additional information.

Concentrations of Credit Risk and Other Uncertainties

Concentrations of Credit Risk and Other Uncertainties—Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents and short-term investments. Risks associated with cash, cash equivalents, short-term investments are mitigated by the Company’s investment policy, which limits the Company’s investing to securities having specified credit ratings. Management believes that the Company is not exposed to significant credit risk.

The Company is subject to certain risks and uncertainties, including, but not limited to changes in any of the following areas that the Company believes could have a material adverse effect on future financial position or results of operations: the ability to obtain future financing; regulatory approval and market acceptance of, and reimbursement for, the Company’s product candidates; performance of third-party clinical research organizations and manufacturers; development of sales channels; protection of intellectual property; litigation or claims against the Company based on intellectual property, patent, product, regulatory or other factors; and the Company’s ability to attract and retain employees necessary to support growth.

Property and Equipment

Property and Equipment—Property and equipment are recorded at cost, net of accumulated depreciation and amortization. Depreciation is recorded using the straight-line method over the estimated useful lives of the assets, generally three to five years. Leasehold improvements are capitalized and amortized over the shorter period of their expected lives or the lease term. Major replacements and improvements are capitalized, while general repairs and maintenance are expensed as incurred.

Impairment of Long-Lived Assets

Impairment of Long-Lived Assets—Long-lived assets, including property and equipment and finite-lived intangible assets, are reviewed for impairment whenever facts or circumstances either internally or externally may indicate that the carrying value of an asset may not be recoverable. If there is an indication of impairment, the Company tests for recoverability by comparing the estimated undiscounted future cash flows expected to result from the use of the asset to the carrying amount of the asset or asset group. If the asset or asset group is determined to be impaired, any excess of the carrying value of the asset or asset group over its estimated fair value is recognized as an impairment loss.

Leases

Leases — For long-term operating leases, the Company recognizes a right-of-use asset and a lease liability on the Company's consolidated balance sheets. The Company determines if an arrangement contains a lease and the classification of the lease at inception. An arrangement contains a lease if there is an identified asset and if the Company controls the use of the identified asset throughout the period of use. The lease liability is determined as the present value of future lease payments and lease incentives over the expected lease term. Lease incentives are included in the measurement of the consideration in the contract at lease commencement when the Company is reasonably certain to incur costs to construct lessee assets. In order to determine the incremental borrowing rate, the Company determines its credit rating, adjusts the credit rating for the nature of the collateral, and benchmarks the borrowing rate against observable yields on comparable securities with a similar term. The incremental borrowing rate, the ROU asset and the lease liability are reevaluated upon a lease modification. It bases the ROU asset on the lease liability adjusted for any prepaid or deferred rent. The Company elected to combine lease and non-lease components for all underlying assets groups. The Company determines the lease term at the commencement date by considering whether renewal options and termination options are reasonably assured of exercise. For short term leases, the Company does not recognize a right-of-use asset and lease liability and recognizes the lease expense over the term of the lease on a straight-line basis.

Rent expense for operating leases is recognized on a straight-line basis over the lease term and is included in operating expenses on the statements of operations and comprehensive loss. The variable lease payments primarily consist of common area maintenance and other operating costs.

The Company assesses the probability of collecting lease payments under its sublease at each reporting date. The Company currently does not deem the collection of lease payments probable and therefore sublease income is constrained at the lesser of cash payments or straight-line sublease income. Sublease income/loss for operating leases is classified in general and administrative expenses based on payments collected and tenant improvement allowance disbursed to the subtenant.

Revenue Recognition

Revenue Recognition—The Company has primarily generated revenue through license, research and collaboration arrangements with its strategic partners.

The Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the Company expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that the Company determines are within the scope of ASC 606, Revenue from Contracts with Customers, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies a performance obligation. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied.

Research and Development Expenses

Research and Development Expenses—Research and development expenses are charged to expense as incurred. Research and development expenses include primarily personnel-related costs, stock-based compensation expense, laboratory supplies, consulting costs, external contract research and development expenses, including expenses incurred under agreements with contract research organizations (“CROs”), the cost of acquiring, developing and manufacturing clinical trial materials, and overhead expenses, such as rent, equipment depreciation, insurance and utilities. Advance payments for goods or services for future research and development activities are deferred and expensed as the goods are delivered or the related services are performed.

The Company estimates research and clinical trial expenses based on the services performed pursuant to contracts with research institutions and clinical research organizations that conduct and manage nonclinical studies and clinical trials on the Company’s behalf. In accruing service fees, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. These estimates are based on communications with the third-party service providers and the Company’s estimates of accrued expenses and on information available at each balance sheet date. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company adjusts the accrual accordingly.

Fair Value Measurements

Fair Value Measurements—Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. The carrying amounts of the Company’s financial instruments, including cash equivalents approximate their fair values due to their short-term maturities. See Note 4, Fair Value Measurements for the methodologies and assumptions used in valuing financial instruments.

Stock-based Compensation Expense

Stock-based Compensation Expense—Stock-based compensation expense related to stock awards to employees is measured at fair value of the award on the date of the grant. The Company estimates the grant-date fair value, and the resulting stock-based compensation expense, using the Black-Scholes valuation model for stock options and employee stock purchase and using intrinsic value, which is the closing price of its common stock on the date of the grant, for restricted stock units (“RSUs”) and performance stock units (“PSUs”). Expense recognition of PSU and performance-based options commences when the associated performance-based criteria are determined to be probable.

The fair value of the award that is ultimately expected to vest is recognized as expense on a straight-line basis over the requisite service period, which is generally the vesting period.

The Black-Scholes valuation model requires the use of following assumptions:

Expected Term—The expected term assumption represents the period that the Company’s stock-based awards are expected to be outstanding and is determined using the simplified method.

Expected Volatility—Expected volatility is based on the Company’s historical stock price volatility.

Expected Dividend—The Black-Scholes valuation model calls for a single expected dividend yield as an input. The Company has never paid dividends and has no plans to pay dividends.

Risk-Free Interest Rate—The risk-free interest rate is based on the U.S. Treasury zero-coupon issues in effect at the time of grant for periods corresponding with the expected term of option.

Income Taxes

Income Taxes—The Company accounts for income taxes using the asset and liability method. The Company records deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns. Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse.

In evaluating the ability to recover its deferred income tax assets, the Company considers all available positive and negative evidence, including its operating results, ongoing tax planning and forecasts of future taxable income on a jurisdiction-by-jurisdiction basis. In the event the Company determines that it would be able to realize its deferred income tax assets in the future in excess of their net recorded amount, it would make an adjustment to the valuation allowance that would reduce the provision for income taxes. Conversely, in the event that all or part of the net deferred tax assets are determined not to be realizable in the future, an adjustment to the valuation allowance would be charged to earnings in the period when such determination is made. As of December 31, 2024 and 2023, the Company has recorded a full valuation allowance on its deferred tax assets.

Tax benefits related to uncertain tax positions are recognized when it is more likely than not that a tax position will be sustained upon examination. Interest and penalties related to unrecognized tax liabilities are included within the provision for income tax.

Comprehensive Loss

Comprehensive Loss—Comprehensive loss comprises net loss and other comprehensive loss. Other comprehensive loss consists of foreign currency translation adjustments and unrealized gain or loss on marketable securities.

Basic and Diluted Net Loss Per Share

Basic and Diluted Net Loss Per Share— Basic net loss per share is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding for the period. Diluted net loss per share is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period using the treasury stock method. Outstanding stock options, RSUs, and employee stock purchase plan (“ESPP”) are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive.

Recent Accounting Pronouncements and Recently Adopted Accounting Pronouncements

Recent Accounting Pronouncements

In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (“ASU 2024-03”). ASU 2024-03 requires disaggregated disclosures of certain categories of expenses in the notes to the financial statements that are included in expense line items on the face of the income statement in annual and interim periods. ASU 2024-03 is effective for annual periods beginning after December 15, 2026 and interim periods beginning after December 15, 2027. The Company is evaluating the impact of this guidance on its financial statements and related disclosures.

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (“ASU 2023-09”). ASU 2023-09 requires enhanced annual disclosures regarding the rate reconciliation and income taxes paid. ASU 2023-09 is effective for annual periods beginning after December 15, 2024 and may be adopted on a prospective or retrospective basis. Early adoption is permitted. The Company is evaluating the impact of this guidance on its financial statements and related disclosures.

In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (“ASU 2023-07”). The amendments in ASU 2023-07 are intended to improve reportable segment disclosure, primarily through enhanced disclosures about significant segment expenses. ASU 2023-07 is effective for annual periods beginning after December 15, 2023, and interim periods beginning after December 15, 2024. The amendments in this ASU should be applied retrospectively to all prior periods presented in the financial statements. The Company retrospectively adopted ASU 2023-07 on December 31, 2024. The adoption of ASU 2023-07 did not have a material financial impact on the Company’s consolidated financial statements.