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Collaboration and Other Agreements, Janssen Biotech, Inc. (Details) - USD ($) $ in Thousands | 1 Months Ended | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jul. 31, 2016 | Jan. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2018 | Sep. 30, 2018 | Jun. 30, 2018 | Mar. 31, 2018 | Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Collaboration and Other Agreements [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  | $ 15,794 | $ 20,798 | $ 18,834 | $ 4,695 | $ 152,359 | $ 1,663 | $ 1,666 | $ 2,055 | $ 60,121 | $ 157,742 | $ 91,880
Janssen MGD011 Agreement | Janssen Biotech Inc. |  |  |  |  |  |  |  |  |  |  |  |  |  |
Collaboration and Other Agreements [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Sale of common stock (in shares) |  |  | 1,923,077 |  |  |  |  |  |  |  |  |  |  |
Proceeds of stock sale |  | $ 75,000 | $ 75,000 |  |  |  |  |  |  |  |  |  |  |
Non-refundable upfront payment |  |  |  |  |  |  |  |  |  |  |  |  |  | 50,000
Janssen MGD015 Agreement | Janssen Biotech Inc. |  |  |  |  |  |  |  |  |  |  |  |  |  |
Collaboration and Other Agreements [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Non-refundable upfront payment | $ 75,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues From License Agreements | Janssen MGD011 Agreement | Janssen Biotech Inc. |  |  |  |  |  |  |  |  |  |  |  |  |  |
Collaboration and Other Agreements [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  | 0 |  | 2,000
Revenues From License Agreements | Janssen MGD015 Agreement | Janssen Biotech Inc. |  |  |  |  |  |  |  |  |  |  |  |  |  |
Collaboration and Other Agreements [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  | $ 0 | $ 600 | $ 75,800

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