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. 29, 2012	$ 193,697	$ 559	$ 33,923	$ 159,195	$ 20
Balance (in shares) at Dec. 29, 2012	55,903	55,903
Net income	53,656	0	0	53,656	0
Other comprehensive income:
Unrealized gain on available-for-sale marketable debt securities, net of tax	2	0	0	0	2
Exercise of common stock options	7,108	6	7,102	0	0
Exercise of common stock options (in shares)		602
Tax effect from stock-based compensation	721	0	721	0	0
Stock-based compensation	3,058	1	3,057	0	0
Stock-based compensation (in shares)		175
Repurchases of common stock	(32,054)	(14)	(32,040)	0	0
Repurchases of common stock (in shares)		(1,438)
Balance at Sep. 28, 2013	$ 226,188	$ 552	$ 12,763	$ 212,851	$ 22
Balance (in shares) at Sep. 28, 2013	55,242	55,242