Acquisitions - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended
	Sep. 30, 2020	Feb. 28, 2019	Mar. 31, 2021	Sep. 30, 2020	Mar. 31, 2020	Dec. 31, 2020
Oscine
Business Acquisition [Line Items]
Business acquisition, consideration transferred	$ 8,500,000
Oscine | Stock Purchase Agreement
Business Acquisition [Line Items]
Business acquisition, percentage of voting interests acquired	100.00%			100.00%
Business acquisition, consideration transferred	$ 8,500,000			$ 8,500,000
Business acquisition, consideration transferred, cash	7,600,000
Business acquisition, consideration holdback amount	900,000
Oscine | Stock Purchase Agreement | Maximum
Business Acquisition [Line Items]
Future milestone payments upon achievement of certain development and commercial milestones	$ 225,800,000			$ 225,800,000
Cobalt Biomedicine Inc | Acquisition Agreement
Business Acquisition [Line Items]
Business acquisition, percentage of voting interests acquired		100.00%
Maximum success payment upon achievement of certain pre-specified development milestones		$ 500,000,000.0
Maximum period for success payment to achieve		20 years
Estimated fair value of success payment liability			$ 156,500,000			$ 64,700,000
Estimated fair value of contingent consideration			133,300,000			$ 121,900,000
Research and development expense in connection with change in fair value of success payment			91,800,000		$ 300,000
Research and development expense in connection with change in fair value of contingent consideration			$ 11,400,000		$ 400,000
Cobalt Biomedicine Inc | Acquisition Agreement | Market Capitalization Equal to or Exceeds $8.1 billion
Business Acquisition [Line Items]
Cobalt success payment		$ 500,000,000.0
Cobalt Biomedicine Inc | Acquisition Agreement | Minimum [Member]
Business Acquisition [Line Items]
Threshold market capitalization		$ 8,100,000,000