Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands		Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]
Beginning balance at Dec. 31, 2018		$ 132,585	$ 54	$ (177,905)	$ 307,014	$ (215)	$ 3,637
Beginning balance, shares at Dec. 31, 2018			54,117,325	26,326,280
Issuance of common stock from exercise of options		23			23
Issuance of common stock from exercise of options, shares			10,000
Issuance of common stock from restricted stock awards, shares			112,545
Purchase of common stock through stock buyback		(3,125)		$ (3,125)
Purchase of common stock through stock buyback, shares				220,297
Impact of net settlements		(868)			(868)
Impact of net settlements, shares			6,391	6,391
Stock-based compensation expense		3,179			3,179
Comprehensive income:
Unrealized gain (loss) on foreign currency exchange		41				41
Net income		3,290					3,290
Ending balance at Mar. 31, 2019		135,125	$ 54	$ (181,030)	309,348	(174)	6,927
Ending balance, shares at Mar. 31, 2019			54,246,261	26,552,968
Beginning balance at Dec. 31, 2018		132,585	$ 54	$ (177,905)	307,014	(215)	3,637
Beginning balance, shares at Dec. 31, 2018			54,117,325	26,326,280
Comprehensive income:
Net income		12,792
Ending balance at Sep. 30, 2019		147,771	$ 55	$ (182,630)	314,384	(467)	16,429
Ending balance, shares at Sep. 30, 2019			54,666,417	26,664,930
Beginning balance at Mar. 31, 2019		135,125	$ 54	$ (181,030)	309,348	(174)	6,927
Beginning balance, shares at Mar. 31, 2019			54,246,261	26,552,968
Issuance of common stock from exercise of options, shares			56,207
Issuance of common stock from restricted stock awards		(1,600)		$ (1,600)
Issuance of common stock from restricted stock awards, shares				97,427
Purchase of common stock through stock buyback		3,762			3,762
Comprehensive income:
Unrealized gain (loss) on foreign currency exchange		(58)				(58)
Net income		4,151					4,151
Ending balance at Jun. 30, 2019		141,380	$ 54	$ (182,630)	313,110	(232)	11,078
Ending balance, shares at Jun. 30, 2019			54,302,468	26,650,395
Issuance of common stock from exercise of options		96	$ 1		95
Issuance of common stock from exercise of options, shares			16,000
Issuance of common stock from restricted stock awards, shares			333,414
Impact of net settlements		(1,751)			(1,751)
Impact of net settlements, shares			14,535	14,535
Stock-based compensation expense		2,930			2,930
Comprehensive income:
Unrealized gain (loss) on foreign currency exchange		(235)				(235)
Net income		5,351					5,351
Ending balance at Sep. 30, 2019		147,771	$ 55	$ (182,630)	314,384	(467)	16,429
Ending balance, shares at Sep. 30, 2019			54,666,417	26,664,930
Beginning balance at Dec. 31, 2019		152,951	$ 55	$ (184,972)	317,675	(319)	20,512
Beginning balance, shares at Dec. 31, 2019			54,903,824	26,761,305
Issuance of common stock from restricted stock awards, shares			123,027
Purchase of common stock through stock buyback		(14,824)		$ (14,824)
Purchase of common stock through stock buyback, shares				736,760
Impact of net settlements		(68)			(68)
Impact of net settlements, shares			230	230
Stock-based compensation expense	[1]	5,294			5,294
Comprehensive income:
Unrealized gain (loss) on investments		(132)				(132)
Unrealized gain (loss) on foreign currency exchange		(53)				(53)
Net income		2,207					2,207
Ending balance at Mar. 31, 2020		145,375	$ 55	$ (199,796)	322,901	(504)	22,719
Ending balance, shares at Mar. 31, 2020			55,027,081	27,498,295
Beginning balance at Dec. 31, 2019		$ 152,951	$ 55	$ (184,972)	317,675	(319)	20,512
Beginning balance, shares at Dec. 31, 2019			54,903,824	26,761,305
Issuance of common stock from exercise of options, shares		37,500
Comprehensive income:
Unrealized gain (loss) on investments		$ (36)
Net income		13,762
Ending balance at Sep. 30, 2020		162,256	$ 56	$ (199,796)	327,899	(177)	34,274
Ending balance, shares at Sep. 30, 2020			55,608,094	27,509,387
Beginning balance at Mar. 31, 2020		145,375	$ 55	$ (199,796)	322,901	(504)	22,719
Beginning balance, shares at Mar. 31, 2020			55,027,081	27,498,295
Issuance of common stock from restricted stock awards, shares			8,000
Stock-based compensation expense		3,293			3,293
Comprehensive income:
Unrealized gain (loss) on investments		84				84
Unrealized gain (loss) on foreign currency exchange		21				21
Net income		4,773					4,773
Ending balance at Jun. 30, 2020		153,546	$ 55	$ (199,796)	326,194	(399)	27,492
Ending balance, shares at Jun. 30, 2020			55,035,081	27,498,295
Issuance of common stock from restricted stock awards		461	$ 1		460
Issuance of common stock from restricted stock awards, shares			561,921
Impact of net settlements		(3,078)			(3,078)
Impact of net settlements, shares			11,092	11,092
Stock-based compensation expense		4,323			4,323
Comprehensive income:
Unrealized gain (loss) on investments		12				12
Unrealized gain (loss) on foreign currency exchange		210				210
Net income		6,782					6,782
Ending balance at Sep. 30, 2020		$ 162,256	$ 56	$ (199,796)	$ 327,899	$ (177)	$ 34,274
Ending balance, shares at Sep. 30, 2020			55,608,094	27,509,387

[1] Includes $1.8 million of accrued compensation expense from 2019.