Share-based compensation - Schedule Assumptions used in Determining Fair Value of Stock Options (Details) - Employee stock option - $ / shares |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Assumptions for Stock Awards Granted [Abstract] | ||||
| Share price at grant date, minimum (in USD per share) | $ 28.63 | $ 46.05 | $ 28.63 | $ 46.05 |
| Share price at grant date, maximum (in USD per share) | 29.06 | 62.94 | 29.60 | 70.05 |
| Exercise price, minimum (in USD per share) | 28.63 | 46.05 | 28.63 | 46.05 |
| Exercise price, maximum (in USD per share) | $ 29.06 | $ 62.94 | $ 29.60 | $ 70.05 |
| Expected volatility, minimum | 52.92% | 55.24% | 52.92% | 55.24% |
| Expected volatility, maximum | 53.65% | 57.04% | 55.78% | 66.17% |
| Expected life (years) | 5 years 6 months | 5 years 6 months | 5 years 6 months | |
| Risk free rate, minimum | 3.94% | 4.34% | 3.94% | 3.93% |
| Risk free rate, maximum | 4.12% | 4.56% | 4.41% | 4.56% |
| Minimum | ||||
| Assumptions for Stock Awards Granted [Abstract] | ||||
| Expected life (years) | 5 years | |||
| Fair value (in USD per share) | $ 15.11 | $ 25.23 | $ 15.11 | $ 25.23 |
| Maximum | ||||
| Assumptions for Stock Awards Granted [Abstract] | ||||
| Expected life (years) | 5 years 6 months | |||
| Fair value (in USD per share) | $ 15.27 | $ 34.99 | $ 16.21 | $ 40.47 |