Loss per share (Details) - CHF (SFr) SFr / shares in Units, SFr in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Numerator
Net loss attributable to equity holders of the Company	SFr (21,189)	SFr (22,760)	SFr (40,218)	SFr (40,622)
Denominator
Weighted-average number of shares outstanding used to compute EPS basic attributable to equity holders	100,631,371	99,549,910	100,519,884	99,467,690
Weighted-average number of shares outstanding used to compute EPS diluted attributable to equity holders	100,631,371	99,549,910	100,519,884	99,467,690
Basic loss per share for the period attributable to equity holders	SFr (0.21)	SFr (0.23)	SFr (0.4)	SFr (0.41)
Diluted loss per share for the period attributable to equity holders	SFr (0.21)	SFr (0.23)	SFr (0.4)	SFr (0.41)

The weighted average number of ordinary shares outstanding plus the weighted average number of ordinary shares that would be issued on the conversion of all the dilutive potential ordinary shares into ordinary shares. [Refer: Ordinary shares [member]; Weighted average [member]]

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The amount of profit (loss) attributable to ordinary equity holders of the parent entity (the numerator) divided by the weighted average number of ordinary shares outstanding during the period (the denominator).

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The amount of profit (loss) attributable to ordinary equity holders of the parent entity (the numerator), divided by the weighted average number of ordinary shares outstanding during the period (the denominator), both adjusted for the effects of all dilutive potential ordinary shares. [Refer: Ordinary shares [member]; Weighted average [member]]

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The profit (loss) attributable to ordinary equity holders of the parent entity. [Refer: Profit (loss)]

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The number of ordinary shares outstanding at the beginning of the period, adjusted by the number of ordinary shares bought back or issued during the period multiplied by a time-weighting factor.

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