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Fair Value of Financial Instruments - Schedule of Change in Fair Value of Success Payment Liabilities Based on Level 3 Inputs (Details) - Success Payment Liabilities $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($)
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 71,200
Payments	(30,000)
Change in fair value	44,200
Balance at June 30, 2021	85,400
Harvard
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	35,500
Payments	(15,000)
Change in fair value	22,100
Balance at June 30, 2021	42,600
Broad Institute
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	35,700
Payments	(15,000)
Change in fair value	22,100
Balance at June 30, 2021	$ 42,800

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+ References

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- Definition

Amount of settlements of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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- Definition

Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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Amount of addition (reduction) to the amount at which a liability could be incurred (settled) in a current transaction between willing parties.

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