Fair Value Measurement (Levels 1-3) (Details) (Measured on a Recurring Basis, USD $) In Thousands, unless otherwise specified	Dec. 28, 2014	Mar. 30, 2014
Quoted Prices in Active Markets for Identical Assets (Level 1)
Cash Equivalents and Short-Term Investments:
US government treasuries and agencies securities	$ 118,987	$ 112,253
Money market funds	62,968	53,430
Asset-backed securities	0	0
Corporate bonds	0	0
International government bonds	0	0
Corporate commercial paper	0	0
Bank deposits	0	0
Repurchase agreement	0	0
Municipal bonds	0	0
Total assets measured at fair value	181,955	165,683
Liabilities:
Fair value of contingent consideration		0
Total liabilities measured at fair value		0
Significant Other Observable Inputs (Level 2)
Cash Equivalents and Short-Term Investments:
US government treasuries and agencies securities	0	0
Money market funds	0	0
Asset-backed securities	26,076	22,332
Corporate bonds	208,327	199,806
International government bonds	1,001	3,014
Corporate commercial paper	11,394	6,246
Bank deposits	13,667	18,538
Repurchase agreement	194	46
Municipal bonds	7,014	9,210
Total assets measured at fair value	267,673	259,192
Liabilities:
Fair value of contingent consideration		0
Total liabilities measured at fair value		0
Significant Unobservable Inputs (Level 3)
Cash Equivalents and Short-Term Investments:
US government treasuries and agencies securities	0	0
Money market funds	0	0
Asset-backed securities	0	0
Corporate bonds	0	0
International government bonds	0	0
Corporate commercial paper	0	0
Bank deposits	0	0
Repurchase agreement	0	0
Municipal bonds	0	0
Total assets measured at fair value	0	0
Liabilities:
Fair value of contingent consideration		2,140
Total liabilities measured at fair value		2,140
Total
Cash Equivalents and Short-Term Investments:
US government treasuries and agencies securities	118,987	112,253
Money market funds	62,968	53,430
Asset-backed securities	26,076	22,332
Corporate bonds	208,327	199,806
International government bonds	1,001	3,014
Corporate commercial paper	11,394	6,246
Bank deposits	13,667	18,538
Repurchase agreement	194	46
Municipal bonds	7,014	9,210
Total assets measured at fair value	449,628	424,875
Liabilities:
Fair value of contingent consideration		2,140
Total liabilities measured at fair value		$ 2,140