v3.25.4
Income taxes - Reconciliation of income tax provision (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Income taxes      
Valuation Allowance $ 145,426 $ 105,854  
Changes in the valuation allowance 39,600    
Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract]      
US federal statutory income tax rate (25,068) (13,511) $ 28,085
Research Credits (5,516) (5,315) 1,260
Nontaxable and nondeductible items, amount      
Non-deductible stock-based compensation 1,106 687 61
Non-deductible executive compensation 622 502 669
Other 14 (19) 34
Other 165 1,769 (1,163)
Changes in the valuation allowance 28,694 16,377 (27,652)
Domestic state and local taxes, net of federal effect 127 175 114
Total tax provision $ 144 $ 665 $ 1,408
Effective Income Tax Rate Reconciliation, Percent [Abstract]      
US federal statutory income tax rate (as a percent) 21.00% 21.00% 21.00%
Research Credits (as a percent) 4.60% 8.30% 0.90%
Nontaxable and nondeductible items, percent      
Non-deductible stock-based compensation (as a percent) (0.90%) (1.10%)  
Non-deductible executive compensation (as a percent) (0.50%) (0.80%) 0.50%
Other (as a percent)
Other (as a percent) (0.10%) (2.40%) (0.80%)
Changes in valuation allowance (as a percent) (24.00%) (25.50%) (20.70%)
Domestic state and local taxes, net of federal effect (as a percent) (0.10%) (0.30%) 0.10%
Total (as a percent) 0.00% (0.80%) 1.00%
Effective Income Tax Rate Reconciliation, State and Local Jurisdiction, Contribution Greater than 50 Percent, Tax Effect [Extensible Enumeration] MASSACHUSETTS MASSACHUSETTS MASSACHUSETTS
United States      
Income taxes      
Net operating loss carryforwards $ 249,400    
State      
Income taxes      
Net operating loss carryforwards 236,400    
Investment tax credit 200    
Research and development tax credits carryforwards | United States      
Income taxes      
Tax credits carryforwards 29,200    
Research and development tax credits carryforwards | State      
Income taxes      
Tax credits carryforwards $ 18,000