v3.25.4
Income Taxes - Reconciliation of the federal income tax rate to the effective tax rate (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Amount    
US federal statutory tax rate $ (9,560) $ (13,601)
Tax credits    
Research and development tax credits (175) (626)
Orphan drug tax credits (4,003) (4,896)
Changes in valuation allowances 12,334 17,422
Share-based payment awards 241 459
Expiration of share-based payment awards 1,159 1,233
Other 4 9
Effective tax rate $ 0 $ 0
Percent    
US federal statutory tax rate 21.00% 21.00%
Tax credits    
Research and development tax credits 0.40% 1.00%
Orphan drug tax credits 8.80% 7.60%
Changes in valuation allowances (27.20%) (27.00%)
Share-based payment awards (0.50%) (0.70%)
Expiration of share-based payment awards (2.50%) (1.90%)
Other 0.00% 0.00%
Effective tax rate 0.00% 0.00%