Summary of significant accounting policies, Segment reporting (Details)	12 Months Ended
Dec. 31, 2021 Segment
Segment reporting [Abstract]
Number of operating segments	1
Number of reportable segments	1

Number of reportable segments reported by the entity.

No definition available.

Name:	aciu_ReportableSegmentsNumber
Namespace Prefix:	aciu_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration