License Revenue - Summary of Changes in Balances of Receivables, Contract Assets and Contract Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Receivables and contract assets:
Accounts receivable, current and non-current, Balance at Beginning of Period	$ 31,599	$ 5,850
Accounts receivable, current and non-current, Net Additions (Deductions)	(469)	52,762
Accounts receivable, current and non-current, Balance at End of Period	31,130	58,612
Contract assets, Balance at Beginning of Period	750	350
Contract assets, Net Additions (Deductions)	250	(100)
Contract assets, Balance at End of Period	1,000	$ 250
Contract liabilities:
Deferred revenue, current and non-current, Balance at Beginning of Period	3,933
Deferred revenue, current and non-current, Balance at End of Period	$ 3,933