| CHF million, except share amounts | 
 | Reporting half-year ended 31.12.2024 | % | 
 | Reporting half-year ended 31.12.2023 | % | 
| Net sales | 
 | 1,421.3 | 100.0 | 
 | 1,376.5 | 100.0 | 
| Cost of goods sold | 
 | –836.9 | –58.9 | 
 | –815.8 | –59.3 | 
| Gross margin | 
 | 584.4 | 41.1 | 
 | 560.7 | 40.7 | 
| Sales and marketing | 
 | –271.7 | –19.1 | 
 | –256.4 | –18.7 | 
| General administration | 
 | –107.0 | –7.5 | 
 | –128.6 | –9.3 | 
| Research and development | 
 | –53.3 | –3.8 | 
 | –69.3 | –5.0 | 
| Other operating income | 
 | 12.6 | 0.9 | 
 | 9.0 | 0.7 | 
| Other operating expenses | 
 | –15.1 | –1.1 | 
 | –27.4 | –2.0 | 
| Operating profit (EBIT) | 
 | 149.9 | 10.5 | 
 | 88.0 | 6.4 | 
| Result from associates | 
 | 0.0 | 0.0 | 
 | 11.5 | 0.8 | 
| Financial expenses | 
 | –20.6 | –1.4 | 
 | –24.5 | –1.8 | 
| Financial income | 
 | 1.4 | 0.1 | 
 | 1.2 | 0.1 | 
| Profit before taxes | 
 | 130.7 | 9.2 | 
 | 76.2 | 5.5 | 
| Income taxes | 
 | –34.0 | –2.4 | 
 | –27.7 | –2.0 | 
| Net profit | 
 | 96.7 | 6.8 | 
 | 48.5 | 3.5 | 
| Net profit attributable to minority interests | 
 | 46.3 | 
 | 
 | 23.6 | 
 | 
| Net profit attributable to the owners of the parent | 
 | 50.4 | 
 | 
 | 24.9 | 
 | 
| Basic earnings per share in CHF | 
 | 12.0 | 
 | 
 | 5.9 | 
 | 
| Diluted earnings per share in CHF | 
 | 11.9 | 
 | 
 | 5.9 | 
 |