Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Accrued clinical costs	$ 3,084	$ 2,495
Accrued employee compensation and related costs	5,712	7,755
Accrued professional fees	4,214	4,118
Accrued sales allowances	14,909	13,471
Accrued royalties	3,863	3,588
Accrued restructuring costs	2,151	0
Other accrued liabilities	9,911	10,411
Total	$ 43,844	$ 41,838