v3.25.4
Income Taxes - Additional Information (Detail) - USD ($)
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Income Tax Disclosure [Line Items]        
Income tax expense (benefit) $ 0 $ 0 $ 0  
Unamortized research and experimental expenditures acceleration period one or two years      
Percentage of research and experimental expense 100.00%      
Cash payments or refunds for income taxes $ 0      
Unrecognized tax benefits $ 13,855,000 $ 14,015,000 $ 13,529,000 $ 12,528,000
Massachusetts [Member]        
Income Tax Disclosure [Line Items]        
Net operating loss carry forwards, expiration year, start 2035      
Future Tax Years [Member] | Maximum [Member]        
Income Tax Disclosure [Line Items]        
Taxable income on NOL 80.00%      
Federal [Member]        
Income Tax Disclosure [Line Items]        
Net operating loss carryforwards $ 616,412,000      
Research and development performance period 5 years      
Federal [Member] | Before 2018 [Member]        
Income Tax Disclosure [Line Items]        
Net operating loss carryforwards $ 98,756,000      
Net operating loss carry forwards, expiration year, start 2035      
Federal [Member] | After 2017 [Member]        
Income Tax Disclosure [Line Items]        
Net operating loss carryforwards $ 517,656,000      
Federal [Member] | Research and Development Tax Credit [Member]        
Income Tax Disclosure [Line Items]        
Tax credit carryforwards $ 55,341,000      
Tax credit carryforwards, expiration year, start 2031      
Federal [Member] | Orphan Drug Credit Carryforwards [Member]        
Income Tax Disclosure [Line Items]        
Tax credit carryforwards $ 25,876,000      
Foreign [Member]        
Income Tax Disclosure [Line Items]        
Research and development performance period 15 years      
State [Member]        
Income Tax Disclosure [Line Items]        
Net operating loss carryforwards $ 597,758,000      
State [Member] | Research and Development Tax Credit [Member]        
Income Tax Disclosure [Line Items]        
Tax credit carryforwards $ 14,767,000      
Tax credit carryforwards, expiration year, start 2028