Collaboration and License Agreements (Additional Information) (Details) $ in Millions	May 01, 2017 USD ($)
NK Agreement [Member]
Related Party Transaction [Line Items]
Milestone payments to be received	$ 100.0

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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