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	473		400			$ 73
Employee stock purchase plan (in shares)						(7)
Exercise of stock options	672		64			$ 608
Exercise of stock options (in shares)						(60)
Amortization of unrecognized stock-based compensation	4,095		4,095
Purchase of treasury stock	(40,049)					$ (40,049)
Purchase of treasury stock (in shares)						636
Foreign currency translation adjustments	(1,673)			(1,673)
Grant of restricted stock units to settle accrued bonus	8,645		8,645
Settlement of restricted stock units	(15,112)		(1,261)		(4,538)	$ (9,313)
Settlement of restricted stock units (in shares)						(359)
Unrealized gain (loss) on investments	168			168
Dividends and dividend equivalent rights	(10,255)		511		(10,766)
Net income	26,282				26,282
Balance at Apr. 03, 2020	323,497	$ 66	257,389	(3,265)	395,646	$ (326,339)
Balances (in shares) at Apr. 03, 2020		65,707				14,161
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
Unrealized gain (loss) on investments	(43)
Net income	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
Balance at Apr. 03, 2020	323,497	$ 66	257,389	(3,265)	395,646	$ (326,339)
Balances (in shares) at Apr. 03, 2020		65,707				14,161
Employee stock purchase plan	432		374			$ 58
Employee stock purchase plan (in shares)						(6)
Exercise of stock options	956		390			$ 566
Exercise of stock options (in shares)						(54)
Amortization of unrecognized stock-based compensation	1,663		1,663
Foreign currency translation adjustments	71			71
Settlement of restricted stock units	(151)		(199)			$ 48
Settlement of restricted stock units (in shares)						(17)
Unrealized gain (loss) on investments	(211)			(211)
Dividends and dividend equivalent rights	(10,036)				(10,036)
Net income	16,346				16,346
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
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	543		485			$ 58
Employee stock purchase plan (in shares)						(6)
Amortization of unrecognized stock-based compensation	3,738		3,738
Foreign currency translation adjustments	243			243
Grant of restricted stock units to settle accrued bonus	7,637		7,637
Settlement of restricted stock units	(15,634)		(3,176)		(1,679)	$ (10,779)
Settlement of restricted stock units (in shares)						(313)
Unrealized gain (loss) on investments	(4)			(4)
Dividends and dividend equivalent rights	(11,261)				(11,261)
Net income	30,848				30,848
Balance at Apr. 02, 2021	377,608	$ 66	274,012	(1,693)	439,717	$ (334,494)
Balances (in shares) at Apr. 02, 2021		65,707				13,584
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 gain (loss) on investments	(65)
Net income	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 Apr. 02, 2021	377,608	$ 66	274,012	(1,693)	439,717	$ (334,494)
Balances (in shares) at Apr. 02, 2021		65,707				13,584
Employee stock purchase plan	480		424			$ 56
Employee stock purchase plan (in shares)						(6)
Amortization of unrecognized stock-based compensation	1,938		1,938
Purchase of treasury stock	(7,000)					$ (7,000)
Purchase of treasury stock (in shares)						79
Foreign currency translation adjustments	(32)			(32)
Settlement of restricted stock units	(32)		(93)			$ 61
Settlement of restricted stock units (in shares)						(9)
Unrealized gain (loss) on investments	(61)			(61)	61
Dividends and dividend equivalent rights	(10,595)				(10,595)
Net income	25,400				25,400
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