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Asset Acquisitions and Contingent Consideration - Schedule of IPR&D Expense (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018
Acquired Finite Lived Intangible Assets [Line Items] |  |  |
Total in process research and development | $ 8,261 | $ 2,000 | $ 49,659
GB001 |  |  |
Acquired Finite Lived Intangible Assets [Line Items] |  |  |
Total in process research and development |  |  | 19,148
GB004 |  |  |
Acquired Finite Lived Intangible Assets [Line Items] |  |  |
Total in process research and development |  |  | 20,000
Other Programs |  |  |
Acquired Finite Lived Intangible Assets [Line Items] |  |  |
Total in process research and development | 761 | 1,000 | 3,011
GB1275 |  |  |
Acquired Finite Lived Intangible Assets [Line Items] |  |  |
Total in process research and development | $ 7,500 | $ 1,000 | $ 7,500

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