Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

No definition available.

Name:	us-gaap_SubsequentEventLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Subsequent events (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
Subsequent events (Details) - USD ($) $ in Thousands	Oct. 31, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Subsequent Event [Line Items]
Collaboration and grant revenue		$ 73	$ 973	$ 249	$ 1,186
Subsequent Event
Subsequent Event [Line Items]
Collaboration and grant revenue	$ 20,000