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Revenue Recognition (Details) - USD ($) $ in Thousands | 1 Months Ended | 3 Months Ended | 9 Months Ended
--- | --- | --- | ---
Oct. 31, 2019 | Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018
Research and Development Arrangements [Line Items] |  |  |  |  |
Development revenue recognized |  | $ 4,771 | $ 454 | $ 5,810 | $ 2,270
Reimbursement revenue recognized |  | $ 4,600 |  |  |
Customer Concentration Risk | Revenue Recognized [Member] |  |  |  |  |
Research and Development Arrangements [Line Items] |  |  |  |  |
Concentration risk percentage |  |  |  | 100.00% |
Customer Concentration Risk | Accounts Receivable [Member] |  |  |  |  |
Research and Development Arrangements [Line Items] |  |  |  |  |
Concentration risk percentage |  |  |  | 100.00% |
Subsequent Event |  |  |  |  |
Research and Development Arrangements [Line Items] |  |  |  |  |
Revenue received in cash | $ 4,600 |  |  |  |

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- Definition Aggregate revenue earned during the period from recognition of related party deferred revenue, non-product related activities and revenue earned during the period from non-repayable sum of money awarded to an entity to carry out a specific purpose as provided in grant agreements. + References No definition available. + Details
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