v3.26.1
Shareholders’ equity - Stock-based Compensation (Details) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Weighted average exercise price (in USD per share) $ 4.32 $ 3.34 $ 4.37 $ 3.32
Restricted stock units granted during period (in shares) 0 0 371,500 901,900
Grant date fair value (in USD per share) $ 0 $ 0 $ 4.39 $ 3.29
Allocated share-based compensation expense $ 1,595 $ 764 $ 2,917 $ 2,057
Research and development        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Allocated share-based compensation expense 271 374 687 929
General and administrative        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Allocated share-based compensation expense $ 1,324 $ 390 $ 2,230 $ 1,128
Arbutus Plans        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Options granted during period (in shares) 385,800 762,400 1,338,200 4,706,122