v3.26.1
Segment Information - Information on the Segment and Reconciliation to Net Loss (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Jun. 30, 2025
Mar. 31, 2025
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting [Line Items]            
Total research and development expenses $ 25,468   $ 19,366   $ 50,618 $ 37,131
Total general and administrative expenses 11,202   6,715   19,401 14,869
Net loss (34,488) $ (30,934) (22,016) $ (22,647) (65,422) (44,663)
Reportable Segment            
Segment Reporting [Line Items]            
Total research and development expenses 25,468   19,366   50,618 37,131
Total general and administrative expenses 11,202   6,715   19,401 14,869
Other income 2,182   4,065   4,597 7,337
Net loss (34,488)   (22,016)   (65,422) (44,663)
Rett syndrome | Reportable Segment            
Segment Reporting [Line Items]            
Total research and development expenses 9,890   7,052   20,927 11,576
Batten disease | Reportable Segment            
Segment Reporting [Line Items]            
Total research and development expenses 60   401   238 1,246
Early Discovery | Reportable Segment            
Segment Reporting [Line Items]            
Total research and development expenses 675   720   1,288 2,007
Personnel-related | Reportable Segment            
Segment Reporting [Line Items]            
Total research and development expenses 5,990   5,125   12,446 10,529
Total general and administrative expenses 2,785   2,212   5,411 4,696
Stock-based compensation | Reportable Segment            
Segment Reporting [Line Items]            
Total research and development expenses 2,688   1,575   4,479 3,146
Total general and administrative expenses 5,172   1,833   7,010 4,310
Manufacturing | Reportable Segment            
Segment Reporting [Line Items]            
Total research and development expenses 4,876   3,635   9,073 6,742
Professional and consultant fees | Reportable Segment            
Segment Reporting [Line Items]            
Total general and administrative expenses 1,233   970   2,635 2,247
Office-related | Reportable Segment            
Segment Reporting [Line Items]            
Total general and administrative expenses 496   620   1,106 1,252
Other | Reportable Segment            
Segment Reporting [Line Items]            
Total research and development expenses 1,289   858   2,167 1,885
Total general and administrative expenses $ 1,516   $ 1,080   $ 3,239 $ 2,364