v3.25.4
Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Detail) - USD ($)
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract]    
Expected tax benefit at statutory rate $ (17,612,000) $ (13,730,000)
State and local income taxes, net of federal benefit $ (292,000) $ (246,000)
Effective Income Tax Rate Reconciliation, State and Local Jurisdiction, Contribution Greater than 50 Percent, Tax Effect [Extensible Enumeration] CALIFORNIA CALIFORNIA
Tax credits - Research and development $ (3,224,000) $ (2,614,000)
Nontaxable or nondeductible items:    
Executive compensation expense 456,000 1,626,000
Change in fair value of SAFEs   755,000
Stock-based compensation expense 1,194,000 (1,004,000)
Other (30,000) 11,000
Other provision adjustments 9,000 71,000
Change in valuation allowance 18,401,000 14,231,000
Change in unrecognized tax benefits 1,098,000 900,000
Provision for income taxes $ 0 $ 0
Effective Income Tax Rate Reconciliation, Percent [Abstract]    
Expected tax benefit at statutory rate, percentage 21.00% 21.00%
State and local income taxes, net of federal benefit, percentage 0.35% 0.38%
Tax credits - Research and development, percentage 3.84% 4.00%
Nontaxable or nondeductible items:    
Executive compensation expense, percentage (0.54%) (2.49%)
Change in fair value of SAFEs, percentage 0.00% (1.16%)
Stock-based compensation expense, percentage (1.43%) 1.55%
Other, percentage 0.04% (0.02%)
Other provision adjustments, percentage (0.01%) (0.11%)
Change in valuation allowance, percentage (21.94%) (21.77%)
Change in unrecognized tax benefits, percentage (1.31%) (1.38%)
Provision for income taxes, percentage 0.00% 0.00%