Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Retained Earnings [Member]
Beginning Balance at Dec. 31, 2021	$ 208,530	$ 74	$ 29,054	$ 1,079	$ 178,323
Beginning Balance, shares at Dec. 31, 2021		7,415
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards	411		411
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards, shares		18
Common stock repurchased on vesting of restricted stock units and performance awards	(185)		(185)
Common stock repurchased on vesting of restricted stock units and performance awards, shares		(4)
Share-based compensation expense	1,830		1,830
Company repurchases of common stock	(8,575)	$ (1)	(484)		(8,090)
Company repurchases of common stock, shares		(115)
Cash dividends on common stock	(2,229)				(2,229)
Unrealized income (loss) on investments, net of tax	(14,358)			(14,358)
Net income	288				288
Ending Balance at Mar. 31, 2022	185,712	$ 73	30,626	(13,279)	168,292
Ending Balance, shares at Mar. 31, 2022		7,314
Beginning Balance at Dec. 31, 2022	177,842	$ 69	32,744	(27,594)	172,623
Beginning Balance, shares at Dec. 31, 2022		6,871
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards	339		339
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards, shares		31
Common stock repurchased on vesting of restricted stock units and performance awards	(1,005)		(1,005)
Common stock repurchased on vesting of restricted stock units and performance awards, shares		(11)
Share-based compensation expense	1,928		1,928
Company repurchases of common stock	(8,030)	$ (1)	(447)		(7,582)
Company repurchases of common stock, shares		(91)
Cash dividends on common stock	(2,067)				(2,067)
Unrealized income (loss) on investments, net of tax	3,652			3,652
Net income	819				819
Ending Balance at Mar. 31, 2023	$ 173,478	$ 68	$ 33,559	$ (23,942)	$ 163,793
Ending Balance, shares at Mar. 31, 2023		6,800