Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Impact of Adoption	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Accumulated (Deficit)	Accumulated (Deficit) Impact of Adoption
Beginning balance (in shares) at Dec. 31, 2018			57,331,622		0
Beginning balance at Dec. 31, 2018	$ 428,340	$ (502)	$ 573	$ 1,006,822	$ 0	$ 0	$ (579,055)	$ (502)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchase of treasury stock (in shares)					(23,952,756)
Purchase of treasury stock	(437,962)				$ (437,962)
Exercise of stock options (in shares)			(111,660)
Exercise of stock options	(1,880)		$ (1)	(1,879)
Net income	35,504						35,504
Ending balance (in shares) at Dec. 31, 2019			57,443,282		(23,952,756)
Ending balance at Dec. 31, 2019	27,260		$ 574	1,008,701	$ (437,962)	0	(544,053)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchase of treasury stock (in shares)					(2,682,042)
Purchase of treasury stock	(30,626)				$ (30,626)
Exercise of stock options (in shares)			(2,147,140)		(112,469)
Exercise of stock options	(12,815)		$ (22)	(14,075)	$ 1,282
Reclass of stock options from liability to equity classification	37,661			37,661
Private placement	444			(813)	$ 1,257
Private placement (in shares)					68,857
Net income	149,221						149,221
Ending balance (in shares) at Dec. 31, 2020			59,590,422		(26,678,410)
Ending balance at Dec. 31, 2020	196,775		$ 596	1,059,624	$ (468,613)	0	(394,832)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)			(669,836)		(7,132)
Exercise of stock options	(2,418)		$ (6)	(2,678)	$ 266
Exercise of stock warrants (in shares)			570,595
Exercise of stock warrants	13,898		$ 6	13,892
Stock compensation expense	8,094			8,094
Foreign currency translation adjustment	(8,047)					(8,047)
Net income	101,577						101,577
Ending balance (in shares) at Dec. 31, 2021			60,830,853		(26,685,542)
Ending balance at Dec. 31, 2021	$ 314,715		$ 608	$ 1,084,288	$ (468,879)	$ (8,047)	$ (293,255)