Net Loss Per Share - Reconciliation of Numerator and Denominators in Computing 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
Earnings Per Share [Abstract]
Net loss from continuing operations	$ (42,660)	$ (16,618)	$ (86,239)	$ (45,085)
Shares used in per share calculation	25,431	24,791	25,024	24,780
Net loss from continuing operations per share, basic and diluted	$ (1.68)	$ (0.67)	$ (3.45)	$ (1.82)