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		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net loss from continuing operations	$ (22,453)	$ (18,246)	$ (43,579)	$ (28,467)
Shares used in per share calculation	24,822	24,777	24,817	24,774
Net loss from continuing operations per share, basic and diluted	$ (0.90)	$ (0.74)	$ (1.76)	$ (1.15)