v3.26.1
Stock-based compensation - Stock options (Details) - Stock options - USD ($)
$ / shares in Units, $ in Thousands
 6 Months Ended 12 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Shares      
Outstanding at the beginning of the period (in shares) 3,030,432    
Granted (in shares) 493,000    
Exercised/Released (in shares) (10,375)    
Forfeited/cancelled (in shares) (169,352)    
Outstanding at the end of the period (in shares) 3,343,705   3,030,432
Vested at the end of the period (in shares) 2,099,619    
Weighted-average exercise price per share      
Outstanding at the beginning of the period (in dollars per share) $ 10.53    
Granted (in dollars per share) 6.11    
Exercised/Released (in dollars per share) 3.05    
Forfeited/cancelled (in dollars per share) 7.59    
Outstanding at the end of the period (in dollars per share) 10.05   $ 10.53
Vested at the end of the period (in dollars per share) $ 11.83    
Weighted-average remaining contractual term (years)      
Outstanding at the end of the period 7 years 6 months   7 years 8 months 12 days
Vested at the end of the period 6 years 10 months 24 days    
Aggregate intrinsic value      
Outstanding at the beginning of the period (in dollars) $ 2,731    
Outstanding at the end of the period (in dollars) 262   $ 2,731
Vested at the end of the period (in dollars) $ 156    
Assumptions used to estimate fair value of each stock-based award on the grant date      
Risk-free interest rate (as a percent) 3.90% 3.98%  
Volatility (as a percent) 103.00% 107.00%  
Expected term (years) 5 years 10 months 24 days 5 years 10 months 24 days