Net Loss Per Share (Computation of Loss Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Numerator:
Net loss	$ (5,614)	$ (5,573)
Denominator:
Weighted–average common shares outstanding, basic and diluted	16,971,393	15,432,405
Net loss per common share, basic and diluted (in USD per share)	$ (0.33)	$ (0.36)