Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Components Of Income Tax Expense Benefit [Line Items]
Computed “expected” tax-benefit - Federal	$ (5,267)	$ (9,453)
Computed “expected” tax-benefit - State	(613)	(1,101)
Adjustment of “expected” tax-benefit to actual	(2)	(431)
Meals, entertainment and other	10	10
Non-deductible stock-based compensation	502	574
Fair Market Value Adjustment - Warrants	(4,076)	(4,332)
Impact of U.S. tax reform	21,555	0
Change in valuation allowance	(12,109)	14,733
Income tax expense	$ 0	$ 0