Fair Value Measurements (Details 3)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Dividend rate range	0.00%	0.00%
Minimum [Member]
Risk-free rate range	1.90%	1.80%
Expected life (years) range	3 years 7 months 6 days	4 years 7 months 6 days
Expected volatility range	87.40%	85.60%
Maximum [Member]
Risk-free rate range	2.30%	2.20%
Expected life (years) range	5 years 3 months 18 days	10 years
Expected volatility range	94.10%	97.20%