Income Taxes - Schedule of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Net operating losses	$ 87,142	$ 90,543
Capitalized research and development	2,155	4,504
Accrued expenses	1,310	1,240
Research and development credits	5,282	4,596
Accrued product returns	0	34
Inventory reserve and UNICAP	0	175
Amortization	630	1,680
Depreciation	163	1,533
Deferred revenue	0	475
Other, net	4,432	7,542
Total deferred tax assets	101,114	112,322
Less valuation allowance	(101,114)	(112,322)
Net deferred tax assets	0	0
IPR&D	(17,425)	(17,425)
Total deferred tax liabilities	(17,425)	(17,425)
Net deferred tax liability	$ (17,425)	$ (17,425)