Basis of Presentation and Summary of Significant Accounting Policies - Licensing revenues (Details) $ in Thousands	9 Months Ended
Sep. 30, 2019 USD ($)
License Agreement Terms
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Upfront payment received	$ 4,230

Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130549-203045

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