Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Net loss	$ (14,365)	$ (9,055)
Weighted average common shares outstanding (in shares)	104,788	100,571
Net loss per share, basic and diluted (in dollars per share)	$ (0.14)	$ (0.09)