Basis of preparation and changes to the Company's accounting policies - Functional and reporting currency (Details) - SFr / $ |
6 Months Ended | 12 Months Ended | |
|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Dec. 31, 2025 |
|
| Foreign exchange rates [abstract] | |||
| Closing foreign exchange rate | 0.817 | 0.807 | 0.8 |
| Average foreign exchange rate | 0.795 | 0.873 | 0.84 |