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. 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)
Excess tax benefit for equity incentive 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 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)
Excess tax benefit for equity incentive 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	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 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
Employee stock purchase plan	1,147	0	810	0	0	337
Employee stock purchase plan (in shares)		0				(16)
Exercise of stock options, net of swaps	960	0	67	0	0	893
Exercise of stock options, net of swaps (in shares)		0				(42)
Excess tax benefit for equity incentive plans	5,100	0	5,100	0	0	0
Amortization of unrecognized stock-based compensation	6,792	0	6,792	0	0	0
Purchase of treasury shares	(30,921)	0	0	0		(30,921)
Purchase of treasury shares (in shares)	425	0				425
Foreign currency translation adjustments	(1,017)	0	0	(1,017)	0	0
Grant of restricted stock units to settle accrued bonus	6,008	0	6,008	0	0	0
Settlement of restricted stock units	(6,356)	0	(343)	0	(6,050)	37
Settlement of restricted stock units (in shares)		0				(174)
Unrealized gain on investments	4	0	0	4	0	0
Dividends and dividend equivalent rights	(13,189)	0	541	0	(13,730)	0
Net income	40,701	0	0	0	40,701	0
Balance at Jan. 02, 2015	$ 244,288	$ 16	$ 160,225	$ (904)	$ 246,961	$ (162,010)
Balance (in shares) at Jan. 02, 2015		16,427				3,556