Stock-Based Compensation - Allocated Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 10,695	$ 10,318	$ 23,315	$ 19,037
Selling, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	7,091	7,126	16,212	13,340
Pre-approval commercial manufacturing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	834	634	1,683	1,104
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,770	$ 2,558	$ 5,420	$ 4,593