Net Income (Loss) Per Share - Computation of basic and diluted net loss per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net loss	$ 11,589	$ (11,242)	$ (10,669)	$ (7,652)	$ (24,060)	$ (14,365)	$ (10,322)	$ (46,077)
Net loss from continuing operations	9,589			(8,809)			(12,175)	(48,632)
Income from discontinued operations, net of taxes	$ 2,000			$ 1,157			$ 1,853	$ 2,555
Weighted average common shares outstanding, basic	107,693			106,239			107,418	105,510
Weighted average common shares outstanding, diluted	110,011			106,239			107,418	105,510
Continuing operations, basic (in dollars per share)	$ 0.09			$ (0.08)			$ (0.11)	$ (0.46)
Discontinued operations, basic (in dollars per share)	0.02			0.01			0.02	0.02
Continuing operations, diluted (in dollars per share)	0.09			(0.08)			(0.11)	(0.46)
Discontinued operations, diluted (in dollars per share)	$ 0.02			$ 0.01			$ 0.02	$ 0.02