Collaboration Agreements (Collaboration Revenues - Takeda) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenues under the collaboration agreement	$ 12,010	$ 6,328
Collaborative Arrangement with Takeda [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Amortization of upfront payment	1,887
Development cost reimbursements	795
Collaboration revenues under the collaboration agreement	$ 2,682

The amount of previously reported deferred or unearned revenue that was recognized as revenue during the period. For cash flows, this element primarily pertains to amortization of deferred credits on long-term arrangements. As a noncash item, it is deducted from net income when calculating cash provided by or used in operations using the indirect method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 13.A.3)
-URI http://asc.fasb.org/extlink&oid=65893310&loc=d3e214044-122780

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 13.A.4)
-URI http://asc.fasb.org/extlink&oid=65893310&loc=d3e214044-122780

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

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