Collaborations - Summary of Changes in Accounts Receivable and Contract Liabilities (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Accounts receivable:
Accounts receivable, Balance at Beginning of Period	$ 2,130	$ 4,620
Accounts receivable, Additions	5,575	102,203
Accounts receivable, Deductions	(5,214)	(105,606)
Accounts receivable, Balance at End of Period	2,491	1,217
Contract liabilities:
Deferred revenue, Balance at Beginning of Period	73,931	28,810
Deferred revenue, Additions	62,900	87,477
Deferred revenue, Deductions	(17,049)	(36,673)
Deferred revenue, Balance at End of Period	$ 119,782	$ 79,614