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
Earnings Per Share [Abstract]
Net loss	$ (8,060)	$ (14,655)	$ (14,855)	$ (26,322)
Weighted average common shares outstanding (in shares)	93,745	83,931	90,283	83,697
Net loss per share, basic and diluted (in dollars per share)	$ (0.09)	$ (0.17)	$ (0.16)	$ (0.31)