Net Income (Loss) Per Common 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
Numerator:
Net income (loss)	$ 3,618	$ (8,269)	$ (4,705)	$ 3,470	$ (19,792)	$ (2,844)	$ (9,356)	$ (19,166)
Weighted average number of common shares outstanding (Basic) (in shares)	45,272			44,251			45,112	43,979
Weighted average number of common shares outstanding (Diluted) (in shares)	47,314			46,667			45,112	43,979
Net (loss) income per share (Basic) (in USD per share)	$ 0.08			$ 0.08			$ (0.21)	$ (0.44)
Net (loss) income per share (Diluted) (in USD per share)	$ 0.08			$ 0.07			$ (0.21)	$ (0.44)
Service-based stock options
Denominator for basic and diluted EPS:
Aggregate number of common equivalent shares (related to options, warrants and preferred stock) that have been excluded from computations of diluted net loss per common share (in shares)	2,400			1,600			5,700	5,100
Restricted Stock Units (RSUs)
Denominator for basic and diluted EPS:
Aggregate number of common equivalent shares (related to options, warrants and preferred stock) that have been excluded from computations of diluted net loss per common share (in shares)	0			0			300	200