v3.26.1
Share-based compensation - Option activity and weighted-average assumptions (Details) - 2014 Plan - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Weighted average exercise price          
Total weighted average grant date fair value of options issued during the period (in $ millions)     $ 6.4    
Share options          
Share-based compensation          
Vesting period (in years)     4 years    
Number of ordinary shares          
Outstanding at beginning of the period (in shares)     4,531,991    
Granted (in shares)     869,760    
Forfeited (in shares)     (12,451)    
Expired (in shares)     (16,186)    
Exercised (in shares)     (410,849)    
Outstanding at end of the period (in shares) 4,962,265   4,962,265   4,531,991
Thereof, fully vested and exercisable at end of period (in shares) 2,769,675   2,769,675    
Outstanding and expected to vest after at end of period (in shares) 2,192,590   2,192,590   1,999,315
Weighted average exercise price          
Outstanding at beginning of the period (in dollars per share)     $ 17.04    
Granted (in dollars per share)     11.48    
Forfeited (in dollars per share)     9.58    
Expired (in dollars per share)     37.84    
Exercised (in dollars per share)     16.6    
Outstanding at end of period (in dollars per share) $ 16.05   16.05   $ 17.04
Thereof, fully vested and exercisable at end of period (in dollars per share) $ 19.77   19.77    
Outstanding and expected to vest after at end of the period (in dollars per share)     $ 11.35   $ 11.81
Weighted-average assumptions used to estimate fair value of share options granted during year          
Expected volatility (as a percent) 95.00% 80.00% 95.00%    
Expected volatility, minimum(as a percent)       70.00%  
Expected volatility, maximum(as a percent)       80.00%  
Expected terms (in years) 10 years 10 years 10 years 10 years  
Risk free interest rate (as a percent) 4.68% 4.64%      
Risk free interest rate, minimum (as a percent)     4.21% 4.36%  
Risk free interest rate, maximum (as a percent)     4.68% 4.64%  
Expected dividend yield (as a percent) 0.00% 0.00% 0.00% 0.00%  
Non-Executive Directors | Share options          
Share-based compensation          
Vesting period (in years)     1 year    
One year from grant date | Share options          
Share-based compensation          
Vesting period (in years)     1 year    
Vesting percentage per year     25.00%