Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 32
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-URI http://asc.fasb.org/extlink&oid=82859839&loc=SL82860478-203043

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130539-203045

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130543-203045

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130545-203045

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License and Collaboration Agreements - Takeda Pharmaceutical (Details) - USD ($) $ in Thousands		3 Months Ended
	Jul. 27, 2017	Mar. 31, 2018	Mar. 31, 2017
License Agreements
Transaction price recognized		$ 49,742	$ 3,073
Takeda Pharmaceutical Co. Ltd
License Agreements
Up-front payment received	$ 100,000
Changes occurred in the transaction price of previously delivered goods		0
Transaction price recognized			$ 0
Maximum \| License Agreement \| Achievement of clinical development and regulatory milestones \| Takeda Pharmaceutical Co. Ltd
License Agreements
Potential milestone payments	140,000
Maximum \| License Agreement \| Achievement of sales milestones \| Takeda Pharmaceutical Co. Ltd
License Agreements
Potential milestone payments	$ 100,000
Licenses, collaboration and other revenues \| Takeda Pharmaceutical Co. Ltd
License Agreements
Transaction price recognized		$ 100