Segment information - Narrative (Details) SFr in Millions	12 Months Ended
Dec. 31, 2023 CHF (SFr) co-founder Reporting_Segment numberOfCo-ceo	Dec. 31, 2022 CHF (SFr)
Disclosure of operating segments [line items]
Number of co-founders \| co-founder	3
Number of co-CEOs \| numberOfCo-ceo	2
Non-current assets	SFr 441.7	SFr 330.9
Number of reporting segments \| Reporting_Segment	1
Rest of World
Disclosure of operating segments [line items]
Non-current assets		SFr 1.3

The amount of assets that do not meet the definition of current assets. [Refer: Current assets]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant