Stock-Based Compensation and Warrants (Details 4) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Beginning Balance	$ 14,821	$ 10,566
Issuance of warrants		15,667
Change in fair value of warrant liabilities	(10,738)	(11,412)	$ 3,811
Ending Balance	$ 4,083	$ 14,821	$ 10,566