Collaboration Revenue - Changes in Contract Assets and Contract Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue - related party, Deductions	$ (6,081)	$ (8,684)	$ (21,909)	$ (16,721)
ASU 2014-09 [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue - related party, Balance at beginning of period			137,259	123,783
Deferred revenue - related party, Additions				393
Deferred revenue - related party, Deductions			(21,909)	(16,721)
Deferred revenue - related party, Balance at end of period	115,350	$ 107,455	115,350	$ 107,455
Deferred revenue, Additions			8,383
Deferred revenue, Deductions			(4,183)
Deferred revenue, Balance at end of period	$ 4,200		$ 4,200