Other Assets and Liabilities - Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accrued Expenses
Accrued compensation	$ 1,726	$ 3,971
Accrued social charges	1,018	1,009
Accrued restructuring (see Note 15)	419	879
Customer allowances	6,616	6,541
Accrued contract research organization charges	1,383	1,000
Accrued contract manufacturing organization costs	1,030	2,028
Accrued contract sales organization and marketing costs	0	3,469
Other	2,497	2,798
Total	$ 14,689	$ 21,695