Share capital, Shelf Registration Statement (Details)	Apr. 28, 2021 shares
Shelf Registration Statement [Abstract]
Shares authorized under Shelf Registration Statement (in shares)	350,000,000

The number of common stock, debt securities, warrants, purchase contracts, units, subscription rights or any combination of the foregoing in one or more future public offerings authorized for sale by the entity through a Shelf Registration Statement.

No definition available.

Name:	aciu_ShelfRegistrationStatementSharesAuthorized
Namespace Prefix:	aciu_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant