Collaboration Agreements - Schedule of Significant Changes in Deferred Revenue Balances, IO Collaboration (Details) - USD ($) $ in Thousands |
9 Months Ended | |
|---|---|---|
Sep. 30, 2018 |
Sep. 30, 2017 |
|
| Disaggregation of Revenue [Line Items] | ||
| Increase as a result of cumulative-effect adjustment arising from the adoption of ASC 606 | $ (29,462) | $ (59,116) |
| Sanofi Collaboration Agreement, Immuno-oncology | ||
| Disaggregation of Revenue [Line Items] | ||
| Revenue recognized that was included in deferred revenue at the beginning of the period | (65,159) | |
| 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 | |