Stock-Based Compensation - Schedule of Recognized Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense for employee awards	$ 3,259	$ 3,681	$ 11,368	$ 11,970
Stock-based compensation expense for non-employee awards		9	1	57
Less: stock-based compensation expense capitalized to inventory	(88)		(308)
Total stock-based compensation expense	3,171	3,690	11,061	12,027
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense for employee awards	1,596	2,116	5,268	6,451
Selling, General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense for employee awards	$ 1,663	$ 1,565	$ 6,100	$ 5,519