Consolidated Balance Sheet Details - Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Balance Sheet Related Disclosures [Abstract]
Accrued product returns	$ 0	$ 99
Accrued interest payable, current	0	121
Accrued clinical trial costs	8,657	3,657
Other accrued expenses	1,842	2,497
Accrued expenses	$ 10,499	$ 6,374