Revenue Recognition - Schedule of Changes in Contract Assets and Liabilities (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($)
Capitalized Contract Cost [Line Items]
Total contract assets, Balance at Beginning of Period	$ 6,694
Contract assets, Addition	5,439
Contract assets, Deduction	(5,642)
Total contract assets, Balance at End of Period	6,491
Total contract liabilities, Balance at Beginning of Period	7,623
Contract liabilities, Addition	6,857
Contract liabilities, Deduction	(4,359)
Total contract liabilities, Balance at End of Period	10,121
Unbilled - collaboration and license revenue
Capitalized Contract Cost [Line Items]
Total contract assets, Balance at Beginning of Period	6,694
Contract assets, Addition	5,439
Contract assets, Deduction	(5,642)
Total contract assets, Balance at End of Period	6,491
Deferred revenue
Capitalized Contract Cost [Line Items]
Total contract liabilities, Balance at Beginning of Period	7,623
Contract liabilities, Addition	6,857
Contract liabilities, Deduction	(4,359)
Total contract liabilities, Balance at End of Period	$ 10,121