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Summary of Significant Accounting Policies - Summary of Collaborators that Represent More Than 10% of Total Revenue Earned (Details) - Sales Revenue, Net [Member]	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Servier [Member]
Concentration Risk [Line Items]
Percentage of all significant revenue earned		36.40%	51.60%
Boehringer [Member]
Concentration Risk [Line Items]
Percentage of all significant revenue earned	12.40%	28.60%	24.80%
Takeda [Member]
Concentration Risk [Line Items]
Percentage of all significant revenue earned		16.80%
Gilead [Member]
Concentration Risk [Line Items]
Percentage of all significant revenue earned		11.40%	13.80%
Janssen [Member]
Concentration Risk [Line Items]
Percentage of all significant revenue earned	71.70%

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- Definition

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13531-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef
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-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
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