Collaboration Agreements Schedule of Significant Changes in Deferred Revenue Balances - IO Collaboration (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017
Disaggregation of Revenue [Line Items]
Increase as a result of cumulative-effect adjustment arising from the adoption of ASC 606	$ (84,238)	$ (10,655)
Sanofi Collaboration Agreement, Immuno-oncology
Disaggregation of Revenue [Line Items]
Revenue recognized that was included in deferred revenue at the beginning of the period	(57,331)
Accounting Standards Update 2014-09 \| Sanofi Collaboration Agreement, Immuno-oncology
Disaggregation of Revenue [Line Items]
Increase as a result of cumulative-effect adjustment arising from the adoption of ASC 606	$ 93,643

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.

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-Publisher FASB
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