Stock-based Compensation - Stock-based Compensation Expense for Options Granted and Restricted Stock as Reflected in the Statement of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 38,728	$ 26,078	$ 16,794
Selling, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	26,432	18,613	12,567
Pre-approval commercial manufacturing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	2,622	1,359	446
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 9,674	$ 6,106	$ 3,781