v3.26.1
Share-based compensation - Activities of the share options (Details)
 12 Months Ended
Dec. 31, 2025
USD ($)
shares
$ / shares
Dec. 31, 2024
USD ($)
shares
$ / shares
Dec. 31, 2023
USD ($)
shares
$ / shares
Dec. 31, 2022
USD ($)
shares
$ / shares
Sharebased compensation        
Number of Options, Outstanding as of beginning (in shares) | shares 77,128,678 67,557,594 63,733,455  
Number of Options, Granted (in shares) | shares 14,591,015 17,151,866 10,402,129  
Number of Options, Modification (in shares) | shares     (1,478,068)  
Number of Options, Exercise of share options (in shares) | shares (1,504,062) (1,379,548) (717,256)  
Number of Options, Forfeited/cancelled (in shares) | shares (4,088,911) (6,201,234) (4,382,666)  
Number of Options, Outstanding as of ending (in shares) | shares 86,126,720 77,128,678 67,557,594 63,733,455
Number of Options, Exercisable as of ending (in shares) | shares 55,900,126      
Number of Options, Vested and Expected To Vest as of ending (in shares) | shares 80,609,681      
Weighted Average Exercise Price, Outstanding as of beginning (in dollars per share) | $ / shares $ 2.26 $ 2.61 $ 3.94  
Weighted Average Exercise Price, Granted (in dollars per share) | $ / shares 0.0001823 0.0001823 0.0001823  
Weighted Average Exercise Price, Modification (in dollars per share) | $ / shares     0.0001823  
Weighted Average Exercise Price, Exercise of share options (in dollars per share) | $ / shares 1.37 1.04 0.21  
Weighted Average Exercise Price, Forfeited/cancelled (in dollars per share) | $ / shares 0 0 0.07  
Weighted Average Exercise Price, Outstanding as of ending (in dollars per share) | $ / shares 2 $ 2.26 $ 2.61 $ 3.94
Weighted Average Exercise Price, Exercisable as of ending (in dollars per share) | $ / shares 3.09      
Weighted Average Exercise Price, Vested and Expected To Vest as of ending (US$) | $ / shares $ 2.14      
Weighted Average Remaining Contractual Life, Outstanding (In Years) 6 years 3 months 18 days 5 years 9 months 5 years 10 months 24 days 6 years 4 months 20 days
Weighted Average Remaining Contractual Life, Exercisable as of ending (In Years) 5 years 1 month 13 days      
Weighted Average Remaining Contractual Life, Vested and Expected To Vest as of ending (In Years) 6 years 1 month 17 days      
Weighted Average Grant Date Fair Value, Outstanding as of beginning (in dollars per share) | $ $ 20.04 $ 22.72 $ 24.62  
Weighted Average Grant Date Fair Value, Granted (in dollars per share) | $ 20.26 16.46 14.78  
Weighted Average Grant Date Fair Value, Modification of share options (in dollars per share | $     12.9  
Weighted Average Grant Date Fair Value, Exercise of share options (in dollars per share) | $ 19.63 18.27 30.55  
Weighted Average Grant Date Fair Value, Forfeited/cancelled (in dollars per share) | $ 20.76 19.15 26.03  
Weighted Average Grant Date Fair Value, Outstanding as of ending (in dollars per share) | $ 20.08 $ 20.04 $ 22.72 $ 24.62
Weighted Average Grant Date Fair Value, Exercisable as of ending (in dollars per share) | $ 21.37      
Weighted Average Grant Date Fair Value, Vested and Expected To Vest as of ending (US$) | $ $ 20.17