Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating loss carryforwards
Income Tax Expense (Benefit)	$ 61
Statutory federal income tax rate
Statutory federal income tax rate (as a percent)	34.00%
Reconciliation of actual income tax expense obtained by applying the statutory federal income tax rate
Tax at federal statutory rate	$ (13,636)	$ (14,018)	$ (1,976)
State, net of federal benefit	(1,321)	(1,624)	(260)
Permanent items	1,420	898	580
Research and development credits			(216)
Benefit state rate change	87	180	(941)
Other	9	1	495
Change in valuation allowance	13,502	14,563	$ 2,318
Total	61
Deferred tax assets:
Net operating loss carryforwards	65,626	53,244
Research and development credits	2,233	2,233
Depreciation		26
Accruals and reserves	4,362	1,900
Intangibles	8,309	9,565
Gross deferred tax assets	80,530	66,968
Less valuation allowance	(80,470)	(66,968)
Total deferred tax assets	60
Indefinate-lived intangibles (naked credit)	(61)
Depreciation	(60)
Total deferred tax liabilities	(121)
Equity compensation	100	$ 100
Federal
Operating loss carryforwards
Income Tax Expense (Benefit)	55
Reconciliation of actual income tax expense obtained by applying the statutory federal income tax rate
Total	55
Deferred tax assets:
Net operating loss carryforwards	170,900
State
Operating loss carryforwards
Income Tax Expense (Benefit)	6
Reconciliation of actual income tax expense obtained by applying the statutory federal income tax rate
Total	6
Deferred tax assets:
Net operating loss carryforwards	$ 144,300