Post balance sheet events (Details) - Subsequent Event [Member] $ in Thousands	Feb. 02, 2018 USD ($) ft²
Post balance sheet events [Abstract]
Additional lease space \| ft²	4,300
Purchase of lab equipment \| $	$ 750

The amount agreed to purchase previous tenant's lab equipment under lease contract.

No definition available.

Name:	aciu_PurchaseOfLabEquipment
Namespace Prefix:	aciu_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration