Commitments and Contingencies - Section G (Details) - Research and Development Arrangement - USD ($) $ in Thousands	1 Months Ended	5 Months Ended
Aug. 31, 2017	Dec. 31, 2017
Long-term Purchase Commitment [Line Items]
Termination notice period		45 days
Payments to acquire in-process research and development	$ 400	$ 418

The cash outflows from the purchase of net carrying value allocated to in-process research and development costs and materials acquired in a business combination.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585

Name:	us-gaap_PaymentsToAcquireInProcessResearchAndDevelopment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration