Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Numerator:
Net loss available for common shareholders - basic and diluted	$ (5,241)	$ (4,070)	$ (16,382)	$ (11,102)
Denominator:
Weighted-average shares outstanding - basic and diluted	74,922	52,111	70,828	50,421
Net loss per share - basic and diluted	$ (0.07)	$ (0.08)	$ (0.23)	$ (0.22)