v3.25.2
Stock-based compensation - Stock options (Details) - USD ($)
 6 Months Ended 12 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
Number of Shares      
Balance at the beginning 4,462,517    
Options granted 1,276,597    
Options exercised (99)    
Options forfeited/expired (147)    
Balance at the end 5,738,868   4,462,517
Vested and expected to vest 5,738,868    
Exercisable at the end 3,136,774    
Weighted-Average Exercise Price      
Balance at the beginning (in dollars per share) $ 6.58    
Options granted (in dollars per share) 4.83    
Options exercised (in dollars per share) 4.71    
Options forfeited/expired (in dollars per share) 23.05    
Balance at the end (in dollars per share) 6.19   $ 6.58
Vested and expected to vest (in dollars per share) 6.19    
Exercisable at the end (in dollars per share) $ 6.85    
Term and Intrinsic Value      
Weighted- Average Remaining Contractual Term, Outstanding 7 years 6 months   7 years 4 months 24 days
Weighted Average Remaining Contractual Term - Vested and expected to vest 7 years 6 months    
Weighted- Average Remaining Contractual Term, Exercisable 6 years 3 months 18 days    
Aggregate Intrinsic Value, Outstanding $ 10,766,000   $ 619,000
Aggregate Intrinsic Value - Vested and expected to vest 10,766,000    
Aggregate Intrinsic Value - Exercisable $ 4,042,000    
Weighted average grant date fair value $ 3.77 $ 3.58  
Intrinsic value options exercised   $ 100,000  
Proceeds from exercise of stock options $ 1,000 $ 114,000  
Time-based options      
Term and Intrinsic Value      
Vesting period 4 years    
Total unrecognized compensation cost $ 10,800,000    
Unrecognized compensation cost remaining period 2 years 4 months 24 days    
Performance-based options      
Number of Shares      
Balance at the end 492,729    
Weighted-Average Exercise Price      
Balance at the end (in dollars per share) $ 6.42