v3.25.4
Stock-based compensation - Stock options (Details) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Term and Intrinsic Value    
Proceeds from exercise of stock options $ 275 $ 114
Stock options    
Number of Shares    
Balance at the beginning 4,462,517  
Options granted 1,337,219  
Options exercised (44,792)  
Options forfeited/expired (32,618)  
Balance at the end 5,722,326 4,462,517
Vested and expected to vest 5,722,326  
Exercisable at the end 3,685,879  
Weighted-Average Exercise Price    
Balance at the beginning (in dollars per share) $ 6.58  
Options granted (in dollars per share) 4.92  
Options exercised (in dollars per share) 6.14  
Options forfeited/expired (in dollars per share) 19.88  
Balance at the end (in dollars per share) 6.12 $ 6.58
Vested and expected to vest (in dollars per share) 6.12  
Exercisable at the end (in dollars per share) $ 6.55  
Term and Intrinsic Value    
Weighted- Average Remaining Contractual Term, Outstanding 7 years 1 month 6 days 7 years 4 months 24 days
Weighted Average Remaining Contractual Term - Vested and expected to vest 7 years 1 month 6 days  
Weighted- Average Remaining Contractual Term, Exercisable 6 years 3 months 18 days  
Aggregate Intrinsic Value, Outstanding $ 3,799 $ 619
Aggregate Intrinsic Value - Vested and expected to vest 3,799  
Aggregate Intrinsic Value - Exercisable $ 1,424  
Weighted average grant date fair value $ 3.84 $ 3.26
Intrinsic value options exercised $ 200 $ 100
Proceeds from exercise of stock options 300 $ 100
Total unrecognized compensation cost $ 8,300  
Unrecognized compensation cost remaining period 2 years 1 month 6 days  
Time-based options    
Term and Intrinsic Value    
Vesting period 4 years  
Performance-based options    
Number of Shares    
Exercisable at the end 477,467  
Weighted-Average Exercise Price    
Exercisable at the end (in dollars per share) $ 6.44