v3.25.4
Income Taxes - Reconciliation (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Effective Income Tax Rate Reconciliation, Amount    
Tax effected at statutory rate $ (79,367)  
Effective Income Tax Rate Reconciliation, State and Local Jurisdiction, Contribution Greater than 50 Percent, Tax Effect [Extensible Enumeration] MASSACHUSETTS  
Other items $ (25)  
Stock compensation (7,831)  
Limitation on executive compensation 8,850  
Other 182  
Research & development credits (3,167)  
Orphan drug credits (16,047)  
Change in valuation allowance $ 97,362  
TaxJurisdictionOfDomicileExtensibleEnumeration country:US country:US
Effective Income Tax Rate Reconciliation, Percent    
Tax effected at statutory rate (as percent) 21.00% 21.00%
State taxes (as percent)   5.90%
Other items (as percent) (0.80%)
Stock compensation (as percent) 2.10% (0.50%)
Non-deductible expenses (as percent)   (0.30%)
Limitation on executive compensation (as percent) (2.30%)  
Other (as percent) (0.10%)  
Research and development credits (as percent) 0.80% 5.80%
Orphan drug credits (as percent) 4.30%  
Change in valuation allowance (as percent) (25.80%) (31.10%)
Other foreign jurisdictions    
Effective Income Tax Rate Reconciliation, Amount    
Other items $ 43  
Effective Income Tax Rate Reconciliation, Percent    
Other items (as percent)