Consolidated Statement of Shareholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2011	$ 129,391	$ 564	$ 47,701	$ 81,101	$ 25
Balance (in shares) at Dec. 31, 2011		56,397
Comprehensive income:
Net income	78,094	0	0	78,094	0
Unrealized gain (loss) on available-for-sale marketable debt securities	(5)	0	0	0	(5)
Exercise of common stock options	5,138	7	5,131	0	0
Exercise of common stock options (in shares)		659
Tax effect from stock-based compensation	5,665	0	5,665	0	0
Stock-based compensation (in shares)		170
Stock-based compensation	10,306	1	10,305	0	0
Repurchases of common stock	(34,892)	(13)	(34,879)	0	0
Repurchases of common stock (in shares)		(1,323)
Balance at Dec. 29, 2012	193,697	559	33,923	159,195	20
Balance (in shares) at Dec. 29, 2012		55,903
Comprehensive income:
Net income	60,081	0	0	60,081	0
Unrealized gain (loss) on available-for-sale marketable debt securities	(7)	0	0	0	(7)
Exercise of common stock options	7,966	7	7,959	0	0
Exercise of common stock options (in shares)		757
Tax effect from stock-based compensation	1,007	0	1,007	0	0
Stock-based compensation (in shares)		160
Stock-based compensation	4,232	2	4,230	0	0
Repurchases of common stock	(42,072)	(19)	(42,053)	0	0
Repurchases of common stock (in shares)		(1,919)
Other	316	0	316	0	0
Other (shares)	0
Balance at Dec. 28, 2013	225,220	549	5,382	219,276	13
Balance (in shares) at Dec. 28, 2013	54,901	54,901
Comprehensive income:
Net income	67,974	0	0	67,974	0
Unrealized gain (loss) on available-for-sale marketable debt securities	(47)	0	0	0	(47)
Exercise of common stock options	2,873	2	2,871	0	0
Exercise of common stock options (in shares)		239
Tax effect from stock-based compensation	581	0	581	0	0
Stock-based compensation (in shares)		(96)
Stock-based compensation	6,798	(1)	6,799	0	0
Repurchases of common stock	(46,492)	(22)	(15,633)	(30,837)	0
Repurchases of common stock (in shares)		(2,246)
Balance at Jan. 03, 2015	$ 256,907	$ 528	$ 0	$ 256,413	$ (34)
Balance (in shares) at Jan. 03, 2015	52,798	52,798