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Summary of Significant Accounting Policies - Summary of Collaborators that Represent More Than 10% of Accounts Receivable (Details) - Customer Concentration Risk - Accounts receivable	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Janssen Biotech, Inc. (Janssen)
Concentration Risk [Line Items]
Percentage of significant accounts receivable	40.00%	39.00%
U.S. government
Concentration Risk [Line Items]
Percentage of significant accounts receivable	19.00%	20.00%
Les Laboratoires Servier and Institut de Reserches Servier (collectively, Servier)
Concentration Risk [Line Items]
Percentage of significant accounts receivable	31.00%	14.00%
Takeda
Concentration Risk [Line Items]
Percentage of significant accounts receivable		14.00%
Eli Lilly
Concentration Risk [Line Items]
Percentage of significant accounts receivable		13.00%

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ 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
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
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