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License Agreements - Broad License Agreement - Change in Fair Value of Success Payment Liability (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
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Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items] |  |  |  |
Change in fair value of derivative liabilities | $ 42,300 | $ 8,700 | $ 44,200 | $ 11,400
Broad Institute |  |  |  |
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items] |  |  |  |
Change in fair value of derivative liabilities | $ 21,200 | $ 4,300 | $ 22,100 | $ 5,700

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5618551-113959 + Details
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