v3.26.1
Stock-based compensation - Stock option weighted-average assumptions (Details)
6 Months Ended 12 Months Ended
Jun. 30, 2026
Dec. 31, 2025
weighted-average assumptions fair value of stock option granted    
Expected dividend rate 0.00%  
Employee Stock Option    
weighted-average assumptions fair value of stock option granted    
Expected option term (years) 6 years 25 days 6 years 10 days
Expected volatility 82.81% 79.28%
Risk-free interest rate 3.79% 3.96%