v3.24.0.1
Intangible assets -Schedule of Intangible Assets (Details) - CHF (SFr)
SFr in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Disclosure of detailed information about intangible assets [line items]    
Intangible assets and goodwill at beginning of period SFr 70.3 SFr 57.5
Additions 4.4 22.7
Disposals   (0.5)
Amortization (10.1) (9.3)
Currency Translation (0.1)  
Intangible assets and goodwill at end of the period 64.6 70.3
Gross carrying amount    
Disclosure of detailed information about intangible assets [line items]    
Intangible assets and goodwill at beginning of period 96.9 76.0
Intangible assets and goodwill at end of the period 101.2 96.9
Accumulated depreciation    
Disclosure of detailed information about intangible assets [line items]    
Intangible assets and goodwill at beginning of period (26.6) (18.5)
Intangible assets and goodwill at end of the period (36.6) (26.6)
Patents, licenses and other rights    
Disclosure of detailed information about intangible assets [line items]    
Intangible assets and goodwill at beginning of period 54.2 41.9
Additions 1.2 16.4
Disposals   0.0
Amortization (4.5) (4.1)
Currency Translation 0.0  
Intangible assets and goodwill at end of the period 50.9 54.2
Patents, licenses and other rights | Gross carrying amount    
Disclosure of detailed information about intangible assets [line items]    
Intangible assets and goodwill at beginning of period 69.2 52.8
Intangible assets and goodwill at end of the period 70.4 69.2
Patents, licenses and other rights | Accumulated depreciation    
Disclosure of detailed information about intangible assets [line items]    
Intangible assets and goodwill at beginning of period (15.0) (10.9)
Intangible assets and goodwill at end of the period (19.6) (15.0)
Software    
Disclosure of detailed information about intangible assets [line items]    
Intangible assets and goodwill at beginning of period 14.4 13.8
Additions 3.1 6.3
Disposals   (0.5)
Amortization (5.5) (5.2)
Currency Translation (0.1)  
Intangible assets and goodwill at end of the period 11.9 14.4
Software | Gross carrying amount    
Disclosure of detailed information about intangible assets [line items]    
Intangible assets and goodwill at beginning of period 25.9 21.4
Intangible assets and goodwill at end of the period 29.0 25.9
Software | Accumulated depreciation    
Disclosure of detailed information about intangible assets [line items]    
Intangible assets and goodwill at beginning of period (11.6) (7.6)
Intangible assets and goodwill at end of the period (17.1) (11.6)
Goodwill    
Disclosure of detailed information about intangible assets [line items]    
Intangible assets and goodwill at beginning of period 1.8 1.8
Additions 0.0 0.0
Disposals   0.0
Amortization 0.0 0.0
Currency Translation 0.0  
Intangible assets and goodwill at end of the period 1.8 1.8
Goodwill | Gross carrying amount    
Disclosure of detailed information about intangible assets [line items]    
Intangible assets and goodwill at beginning of period 1.8 1.8
Intangible assets and goodwill at end of the period 1.8 1.8
Goodwill | Accumulated depreciation    
Disclosure of detailed information about intangible assets [line items]    
Intangible assets and goodwill at beginning of period 0.0 0.0
Intangible assets and goodwill at end of the period SFr 0.0 SFr 0.0