CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock and Additional Paid-In Capital	Treasury Stock	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning balances at Dec. 31, 2018	$ 380,087	$ 703,023		$ (844)	$ (322,093)
Repurchase of common stock			$ (25,162)
Stock-based compensation		8,102
Exercise of employee stock options		1,443
Payments for taxes related to net share settlement of equity awards		(4,651)
Retirement of treasury stock		(18,107)	$ 25,162		(7,055)
Other comprehensive income (loss)	30			30
Net loss	(13,228)				(13,228)
Ending balance at Mar. 31, 2019	346,620	689,810		(814)	(342,376)
Beginning balances at Dec. 31, 2019	285,222	671,061		(916)	(384,923)
Stock-based compensation		7,661
Exercise of employee stock options		468
Payments for taxes related to net share settlement of equity awards		(2,312)
Other comprehensive income (loss)	(233)			(233)
Net loss	(16,725)				(16,725)
Ending balance at Mar. 31, 2020	$ 274,081	$ 676,878		$ (1,149)	$ (401,648)