Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Numerator:
Net loss available for common shareholders - basic and diluted	$ (5,494)	$ (3,476)	$ (11,141)	$ (7,032)
Denominator:
Weighted-average shares outstanding - basic and diluted	69,373	51,567	68,747	49,566
Net loss per share - basic and diluted	$ (0.08)	$ (0.07)	$ (0.16)	$ (0.14)