Total Compensation Cost from Share-Based Payments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation cost	$ 37,020	$ 32,403	$ 35,421
Research and development expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation cost	14,297	13,856	15,150
Selling, general and administrative expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation cost	22,723	18,547	20,271
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation cost	546	449	599
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation cost	14,648	16,608	16,364
Stock and stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation cost	$ 21,826	$ 15,346	$ 18,458