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 shares	(40,049)					$ (40,049)
Purchase of treasury shares (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 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. 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 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