Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Common Stock Outstanding [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balances (in shares) at Dec. 31, 2019	32,503		9,294
Balances at Dec. 31, 2019	$ 5	$ 325,197	$ (91,695)	$ (35,870)	$ (1,480)	$ 196,157
Issuance of common stock in connection with employee stock purchase plan (in shares)	89		0
Issuance of common stock in connection with employee stock purchase plan	$ 0	810	$ 0	0	0	810
Issuance of common stock in connection with exercise of options (in shares)	21		0
Issuance of common stock in connection with exercise of options	$ 0	161	$ 0	0	0	161
Vesting of restricted stock units (in shares)	182		0
Vesting of restricted stock units	$ 0	0	$ 0	0	0	0
Purchases of treasury stock in connection with tax withholdings on restricted stock grants (in shares)	0		93
Purchases of treasury stock in connection with tax withholdings on restricted stock grants	$ 0	0	$ (1,478)	0	0	(1,478)
Stock-based compensation expense	0	3,513	0	0	0	3,513
Comprehensive income (loss)	$ 0	0	$ 0	(528)	(166)	(694)
Balances (in shares) at Mar. 31, 2020	32,795		9,387
Balances at Mar. 31, 2020	$ 5	329,681	$ (93,173)	(36,398)	(1,646)	198,469
Balances (in shares) at Dec. 31, 2020	36,850		9,550
Balances at Dec. 31, 2020	$ 6	407,173	$ (96,215)	(76,233)	(225)	234,506
Issuance of common stock in connection with employee stock purchase plan (in shares)	100		0
Issuance of common stock in connection with employee stock purchase plan	$ 0	921	$ 0	0	0	$ 921
Issuance of common stock in connection with exercise of options (in shares)	81		0			81
Issuance of common stock in connection with exercise of options	$ 0	568	$ 0	0	0	$ 568
Vesting of restricted stock units (in shares)	149		0
Vesting of restricted stock units	$ 0	0	$ 0	0	0	0
Purchases of treasury stock in connection with tax withholdings on restricted stock grants (in shares)	0		73
Purchases of treasury stock in connection with tax withholdings on restricted stock grants	$ 0	0	$ (1,463)	0	0	(1,463)
Repurchase of common stock (in shares)	(251)		251
Repurchase of common stock	$ 0	0	$ (4,523)	0	0	(4,523)
Stock-based compensation expense	0	3,369	0	0		3,369
Comprehensive income (loss)	$ 0	0	$ 0	(7,597)	(528)	(8,125)
Balances (in shares) at Mar. 31, 2021	36,929		9,874
Balances at Mar. 31, 2021	$ 6	$ 412,031	$ (102,201)	$ (83,830)	$ (753)	$ 225,253