Stock-Based Compensation - Schedule of Recognized Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense for employee awards	$ 4,577	$ 4,945	$ 8,110	$ 8,289
Stock-based compensation expense for non-employee awards		22	1	48
Less: stock-based compensation expense capitalized to inventory	(90)		(220)
Total stock-based compensation expense	4,487	4,967	7,891	8,337
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	1,804	2,369	3,672	4,335
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	$ 2,773	$ 2,576	$ 4,438	$ 3,954