Collaborative Arrangements - Additional Information (Details)	1 Months Ended	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($) target	Jul. 01, 2021
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative arrangement, research and development expenses		$ 26,800,000			$ 986,800,000
Up-front payment				$ 80,100,000		$ 143,300,000
CRISPR Therapeutics
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative arrangement, right to exclusively license, number of targets | target							3
Collaborative arrangement, development and regulatory potential milestone payments maximum							$ 410,000,000
CRISPR A&R JDCA
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Up-front payment			$ 900,000,000
Collaborative arrangement, development and regulatory potential milestone payments maximum			$ 200,000,000
Allocation of net profits and net losses, percent								60.00%
CRISPR A&R JDCA | CRISPR
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Allocation of net profits and net losses, percent								40.00%
Moderna, Inc.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Up-front payment	$ 75,000,000
Collaborative arrangement, development and regulatory potential milestone payments maximum	$ 380,000,000