Consolidated Statements of Stockholders' Equity (USD $) 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 Dec. 31, 2010	$ 183,800	$ 16	$ 96,089	$ (451)	$ 156,086	$ (67,940)
Balance (in shares) at Dec. 31, 2010		16,427				2,431
Employee stock purchase plan	894	0	222	0	0	672
Employee stock purchase plan (in shares)		0				(21)
Exercise of stock options, net of swaps	1,336	0	(162)	0	(1,484)	2,982
Exercise of stock options, net of swaps (in shares)		0				(102)
Tax benefit for stock option plans	2,378	0	2,378	0	0	0
Amortization of unrecognized stock-based compensation	5,044	0	5,044	0	0	0
Purchase of treasury shares	(40,573)	0	0	0	0	(40,573)
Purchase of treasury shares (in shares)	1,002	0				1,002
Foreign currency translation adjustments	(72)	0	0	(72)	0	0
Grant of restricted stock units to settle accrued bonus	4,538	0	4,538	0	0	0
Settlement of restricted stock units	(3,377)	0	(38)	0	(7,865)	4,526
Settlement of restricted stock units (in shares)		0				(183)
Unrealized gain loss on investments	52	0	0	52	0	0
Net income	32,695	0	0	0	32,695	0
Balance at Dec. 30, 2011	186,715	16	108,071	(471)	179,432	(100,333)
Balance (in shares) at Dec. 30, 2011		16,427				3,127
Employee stock purchase plan	1,008	0	400	0	0	608
Employee stock purchase plan (in shares)		0				(20)
Exercise of stock options, net of swaps	2,607	0	(358)	0	(3,123)	6,088
Exercise of stock options, net of swaps (in shares)		0				(200)
Tax benefit for stock option plans	3,948	0	3,948	0	0	0
Amortization of unrecognized stock-based compensation	6,289	0	6,289	0	0	0
Purchase of treasury shares	(23,395)	0	0	0	0	(23,395)
Purchase of treasury shares (in shares)	480	0				480
Foreign currency translation adjustments	249	0	0	249	0	0
Grant of restricted stock units to settle accrued bonus	5,343	0	5,343	0	0	0
Settlement of restricted stock units	(3,532)	0	0	0	(7,477)	3,945
Settlement of restricted stock units (in shares)		0				(166)
Unrealized gain loss on investments	(28)	0	0	(28)	0	0
Net income	37,225	0	0	0	37,225	0
Balance at Dec. 28, 2012	216,429	16	123,693	(250)	206,057	(113,087)
Balance (in shares) at Dec. 28, 2012		16,427				3,221
Employee stock purchase plan	1,166	0	648	0	0	518
Employee stock purchase plan (in shares)		0				(19)
Exercise of stock options, net of swaps	294	0	(302)	0	(1,031)	1,627
Exercise of stock options, net of swaps (in shares)		0				(61)
Tax benefit for stock option plans	4,267	0	4,267	0	0	0
Amortization of unrecognized stock-based compensation	7,107	0	7,107	0	0	0
Purchase of treasury shares	(25,011)	0	0	0		(25,011)
Purchase of treasury shares (in shares)	438	0				438
Foreign currency translation adjustments	373	0	0	373	0	0
Grant of restricted stock units to settle accrued bonus	5,807	0	5,807	0	0	0
Settlement of restricted stock units	(6,028)	0	(273)	0	(9,352)	3,597
Settlement of restricted stock units (in shares)		0				(216)
Unrealized gain loss on investments	(14)	0	0	(14)	0	0
Dividends and dividend equivalent rights	(7,971)	0	303	0	(8,274)	0
Net income	38,640	0	0	0	38,640	0
Balance at Jan. 03, 2014	$ 235,059	$ 16	$ 141,250	$ 109	$ 226,040	$ (132,356)
Balance (in shares) at Jan. 03, 2014		16,427				3,363