Fair Value Measurement (Details) (Measured on a Recurring Basis, USD $) In Thousands, unless otherwise specified	Sep. 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	$ 119,498	$ 112,253
Money market funds	56,254	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	175,752	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	23,179	22,332
Corporate bonds	211,757	199,806
International government bonds	1,003	3,014
Corporate commercial paper	9,695	6,246
Bank deposits	20,417	18,538
Repurchase agreement	1,132	46
Municipal bonds	8,060	9,210
Total assets measured at fair value	275,243	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	119,498	112,253
Money market funds	56,254	53,430
Asset-backed securities	23,179	22,332
Corporate bonds	211,757	199,806
International government bonds	1,003	3,014
Corporate commercial paper	9,695	6,246
Bank deposits	20,417	18,538
Repurchase agreement	1,132	46
Municipal bonds	8,060	9,210
Total assets measured at fair value	450,995	424,875
Liabilities:
Fair value of contingent consideration		2,140
Total liabilities measured at fair value		$ 2,140