Collaboration Revenue - Changes in Contract Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue - related party, Deductions	$ (6,081)	$ (11,837)	$ (21,909)
ASU 2014-09 [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue - related party, Balance at beginning of period		110,071	137,259
Deferred revenue - related party, Deductions		(10,728)	(21,909)
Deferred revenue - related party, Balance at end of period	115,350	99,343	115,350
Deferred revenue, Balance at beginning of period		9,668
Deferred revenue, Additions		827	8,383
Deferred revenue, Deductions		(2,016)	(4,183)
Deferred revenue, Balance at end of period	$ 4,200	$ 8,479	$ 4,200