Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional paid-in capital [Member]	Accumulated other comprehensive income (loss) [Member]	Retained earnings [Member]	Treasury Stock [Member]
Balance at Jan. 03, 2020	$ 350,251	$ 66	$ 244,935	$ (1,760)	$ 384,668	$ (277,658)
Balances (in shares) at Jan. 03, 2020		65,707				13,951
Employee stock purchase plan	905		774			$ 131
Employee stock purchase plan (in shares)						(13)
Exercise of stock options	1,628		454			$ 1,174
Exercise of stock options (in shares)						(114)
Amortization of unrecognized stock-based compensation	5,758		5,758
Purchase of treasury stock	(40,049)					$ (40,049)
Purchase of treasury stock (in shares)						636
Foreign currency translation adjustments	(1,602)			(1,602)
Grant of restricted stock units to settle accrued bonus	8,645		8,645
Settlement of restricted stock units	(15,263)		(1,460)		(4,538)	$ (9,265)
Settlement of restricted stock units (in shares)						(376)
Unrealized loss on investments	(43)			(43)
Dividends and dividend equivalent rights	(20,291)		511		(20,802)
Net income	42,628				42,628
Balance at Jul. 03, 2020	332,567	$ 66	259,617	(3,405)	401,956	$ (325,667)
Balances (in shares) at Jul. 03, 2020		65,707				14,084
Employee stock purchase plan	479		405			$ 74
Employee stock purchase plan (in shares)						(7)
Amortization of unrecognized stock-based compensation	1,691		1,691
Foreign currency translation adjustments	550			550
Unrealized loss on investments	(129)			(129)
Dividends and dividend equivalent rights	(10,045)				(10,045)
Net income	18,084				18,084
Balance at Oct. 02, 2020	343,197	$ 66	261,713	(2,984)	409,995	$ (325,593)
Balances (in shares) at Oct. 02, 2020		65,707				14,077
Balance at Jan. 01, 2021	361,498	$ 66	265,328	(1,932)	421,809	$ (323,773)
Balances (in shares) at Jan. 01, 2021		65,707				13,903
Employee stock purchase plan	1,023		909			$ 114
Employee stock purchase plan (in shares)						(12)
Amortization of unrecognized stock-based compensation	5,676		5,676
Purchase of treasury stock	(7,000)					$ (7,000)
Purchase of treasury stock (in shares)						79
Foreign currency translation adjustments	211			211
Grant of restricted stock units to settle accrued bonus	7,637		7,637
Settlement of restricted stock units	(15,666)		(3,269)		(1,679)	$ (10,718)
Settlement of restricted stock units (in shares)						(322)
Unrealized loss on investments	(4)			(65)	61
Dividends and dividend equivalent rights	(21,856)				(21,856)
Net income	56,248				56,248
Balance at Jul. 02, 2021	387,767	$ 66	276,281	(1,786)	454,583	$ (341,377)
Balances (in shares) at Jul. 02, 2021		65,707				13,648
Balance at Jan. 01, 2021	361,498	$ 66	265,328	(1,932)	421,809	$ (323,773)
Balances (in shares) at Jan. 01, 2021		65,707				13,903
Unrealized loss on investments	(65)
Net income	80,822
Balance at Oct. 01, 2021	404,989	$ 66	279,250	(2,052)	468,578	$ (340,853)
Balances (in shares) at Oct. 01, 2021		65,707				13,595
Balance at Jul. 02, 2021	387,767	$ 66	276,281	(1,786)	454,583	$ (341,377)
Balances (in shares) at Jul. 02, 2021		65,707				13,648
Employee stock purchase plan	518		471			$ 47
Employee stock purchase plan (in shares)						(5)
Exercise of stock options	1,135		658			$ 477
Exercise of stock options (in shares)						(48)
Amortization of unrecognized stock-based compensation	1,840		1,840
Foreign currency translation adjustments	(266)			(266)
Dividends and dividend equivalent rights	(10,579)				(10,579)
Net income	24,574				24,574
Balance at Oct. 01, 2021	$ 404,989	$ 66	$ 279,250	$ (2,052)	$ 468,578	$ (340,853)
Balances (in shares) at Oct. 01, 2021		65,707				13,595