Stock Compensation - Schedule of Total Compensation Cost from Share-Based Payments (Details) - 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 [Line Items]
Stock-based compensation cost	$ 5,282	$ 9,931	$ 14,659	$ 29,009
Research and development expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation cost	2,329	3,633	6,807	11,629
Selling, general and administrative expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation cost	2,953	6,298	7,852	17,380
Purchases of common stock at a discount
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation cost	110	187	375	433
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation cost	2,459	3,348	7,813	11,718
Stock and stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation cost	$ 2,713	$ 6,396	$ 6,471	$ 16,858