Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands		Total	Reclassification Adjustment [Member]	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] Reclassification Adjustment [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Retained Earnings [Member] Reclassification Adjustment [Member]
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
Treasury Stock Value Acquired Cost Method		(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)	[1]	5,294				5,294
Comprehensive income:
Unrealized gain (loss) on foreign currency exchange		(53)						(53)
Net income		2,207							2,207
Unrealized loss on investments		(132)						(132)
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
Ending balance at Dec. 31, 2020		202,506		$ 56	$ (199,796)	363,055		1,611	37,580
Ending balance (ASU 2020-06) at Dec. 31, 2020			$ (30,267)				$ (30,500)			$ 233
Ending balance, shares at Dec. 31, 2020				55,633,155	27,510,552
Issuance of common stock from restricted stock awards, shares				24,815
Impact of net settlements		(370)				(370)
Impact of net settlements, shares				290	290
Stock-based compensation expense(1)	[1]	7,425				7,425
Comprehensive income:
Unrealized gain (loss) on foreign currency exchange		1,034						1,034
Net income		1,810							1,810
Ending balance at Mar. 31, 2021		$ 182,138		$ 56	$ (199,796)	$ 339,610		$ 2,645	$ 39,623
Ending balance, shares at Mar. 31, 2021				55,658,260	27,510,842

[1] Includes $0.8 and $1.8 million of accrued compensation expense for the three months ended March 31, 2021 and 2020, respectively.