Revenue Recognition - Schedule of Changes in Contract Assets and Liabilities (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Capitalized Contract Cost [Line Items]
Total contract assets, Balance at Beginning of Period	$ 6,694
Contract assets, Addition	10,348
Contract assets, Deduction	(7,170)
Total contract assets, Balance at End of Period	9,872
Total contract liabilities, Balance at Beginning of Period	7,623
Contract liabilities, Addition	6,857
Contract liabilities, Deduction	(7,037)
Total contract liabilities, Balance at End of Period	7,443
Unbilled - collaboration and license revenue
Capitalized Contract Cost [Line Items]
Total contract assets, Balance at Beginning of Period	6,694
Contract assets, Addition	10,348
Contract assets, Deduction	(7,170)
Total contract assets, Balance at End of Period	9,872
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	(7,037)
Total contract liabilities, Balance at End of Period	$ 7,443