Stock-Based Compensation (Details 5) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Beginning Balance	$ 10,567	$ 6,756
Warrants liability	15,667
Change in fair value of warrant liability	(11,412)	3,811	$ (620)
Ending Balance	$ 14,821	$ 10,567	$ 6,756