Investments (Details) (USD $)			3 Months Ended
	Jan. 01, 2012	Apr. 03, 2011	Jan. 01, 2012 Samplify [Member]	Jan. 01, 2012 Non-marketable Equity Securities [Member]	Oct. 02, 2011 Non-marketable Equity Securities [Member]	Jan. 01, 2012 U.S. government treasuries and agency securities [Member]	Apr. 03, 2011 U.S. government treasuries and agency securities [Member]	Jan. 01, 2012 U.S. government agency securities [Member]	Apr. 03, 2011 U.S. government agency securities [Member]	Jan. 01, 2012 Corporate bonds [Member]	Apr. 03, 2011 Corporate bonds [Member]	Jan. 01, 2012 Corporate commercial paper [Member]	Apr. 03, 2011 Corporate commercial paper [Member]	Jan. 01, 2012 Money market funds [Member]	Apr. 03, 2011 Money market funds [Member]	Jan. 01, 2012 Bank deposits [Member]	Apr. 03, 2011 Bank deposits [Member]	Jan. 01, 2012 Municipal bonds [Member]	Apr. 03, 2011 Municipal bonds [Member]	Jan. 01, 2012 Total available-for-sale investments [Member]	Apr. 03, 2011 Total available-for-sale investments [Member]	Jan. 01, 2012 Less amounts classified as cash equivalents [Member]	Apr. 03, 2011 Less amounts classified as cash equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 204,205,000	$ 194,415,000				$ 157,256,000	$ 119,917,000			$ 38,123,000	$ 57,001,000	$ 8,494,000	$ 51,785,000	$ 61,259,000	$ 32,203,000	$ 22,133,000	$ 17,764,000	$ 578,000	$ 368,000	$ 287,843,000	$ 279,038,000	$ (83,638,000)	$ (84,623,000)
Gross Unrealized Gains	63,000	122,000				25,000	17,000			36,000	104,000	0	0	0	0	0	0	2,000	1,000	63,000	122,000	0	0
Gross Unrealized Losses	(68,000)	(25,000)				(2,000)	(8,000)			(71,000)	(18,000)	0	0	0	0	0	0	0	0	(73,000)	(26,000)	5,000	1,000
Estimated Fair Value	204,200,000	194,512,000				157,279,000	119,926,000			38,088,000	57,087,000	8,494,000	51,785,000	61,259,000	32,203,000	22,133,000	17,764,000	580,000	369,000	287,833,000	279,134,000	(83,633,000)	(84,622,000)
Fair value, continuous loss position [Abstract]
Fair Value Less than 12 months	55,809,000	60,707,000						39,663,000	36,531,000	16,146,000	24,176,000
Fair Value 12 months or Greater	0	0						0	0	0	0
Fair Value Total	55,809,000	60,707,000						39,663,000	36,531,000	16,146,000	24,176,000
Gross unrealized losses, continuous loss position [Abstract]
Unrealized Loss Less than 12 months	(74,000)	(26,000)						(10,000)	(8,000)	(64,000)	(18,000)
Unrealized Loss 12 months or Greater	0	0						0	0	0	0
Unrealized Loss Total	(74,000)	(26,000)						(10,000)	(8,000)	(64,000)	(18,000)
Amortized cost, by contractual maturity [Abstract]
Due in 1 year or less	272,059,000
Due in 1-2 years	13,798,000
Due in 2-5 years	1,986,000
Amortized cost of available for sale securities	287,843,000
Fair value, by contractual maturity [Abstract]
Due in 1 year or less	272,083,000
Due in 1-2 years	13,775,000
Due in 2-5 years	1,975,000
Estimated fair value of available for sale securites	287,833,000
Non-marketable equity securities [Abstract]
Cost method investments, carrying value	2,500,000	8,500,000			2,000,000
Other-than temporary impairment loss during period			2,800,000
Proceeds from sale of non-marketable equity security				2,600,000
Recorded gain on sale of non-marketable equity securities				$ 600,000