v3.25.4
Property, plant and equipment - Narrative (Details) - CHF (SFr)
SFr in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Disclosure of detailed information about property, plant and equipment [line items]    
Additions SFr 69.2 SFr 65.1
Noncash additions of property, plant and equipment 0.0 4.6
Leasehold improvements    
Disclosure of detailed information about property, plant and equipment [line items]    
Additions SFr 34.2 35.1
Leasehold improvements | Minimum    
Disclosure of detailed information about property, plant and equipment [line items]    
Useful life measured as period of time, property, plant and equipment 3 years  
Leasehold improvements | Maximum    
Disclosure of detailed information about property, plant and equipment [line items]    
Useful life measured as period of time, property, plant and equipment 8 years  
Trade tools    
Disclosure of detailed information about property, plant and equipment [line items]    
Additions SFr 0.6 0.9
Useful life measured as period of time, property, plant and equipment 3 years  
Production equipment    
Disclosure of detailed information about property, plant and equipment [line items]    
Additions SFr 24.1 10.7
Useful life measured as period of time, property, plant and equipment 2 years  
Furniture and fixtures    
Disclosure of detailed information about property, plant and equipment [line items]    
Additions SFr 6.8 11.2
Furniture and fixtures | Minimum    
Disclosure of detailed information about property, plant and equipment [line items]    
Useful life measured as period of time, property, plant and equipment 5 years  
Furniture and fixtures | Maximum    
Disclosure of detailed information about property, plant and equipment [line items]    
Useful life measured as period of time, property, plant and equipment 8 years  
Other    
Disclosure of detailed information about property, plant and equipment [line items]    
Additions SFr 3.5 7.2
Property, plant and equipment, expenditures recognised in course of its construction SFr 7.9 SFr 7.3
Other | Minimum    
Disclosure of detailed information about property, plant and equipment [line items]    
Useful life measured as period of time, property, plant and equipment 3 years  
Other | Maximum    
Disclosure of detailed information about property, plant and equipment [line items]    
Useful life measured as period of time, property, plant and equipment 8 years