Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Commercial costs	$ 3,874	$ 2,884
Product revenue reserves	14,041	7,620
Royalty payable	2,066	1,735
Research and development costs	8,048	10,403
Payroll and employee benefits	9,949	12,230
Interest	3,050	3,050
Professional fees	2,636	3,465
Restructuring costs	0	613
Other current liabilities	95	203
Total accrued expenses and other current liabilities	$ 43,759	$ 42,203