Marketable Securities - Schedule of Unrealized Losses by Investment Category (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 29, 2013	Mar. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Fair value of less than 12 months	$ 162,373	$ 38,753
Unrealized losses of less than 12 months	(794)	(75)
Fair value of 12 months or greater	2,306
Unrealized losses of 12 months or greater	(38)
Fair value, Total	164,679	38,753
Unrealized losses, Total	(832)	(75)
U.S. government and agency securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of less than 12 months	50,796	4,502
Unrealized losses of less than 12 months	(176)	(1)
Fair value of 12 months or greater
Unrealized losses of 12 months or greater
Fair value, Total	50,796	4,502
Unrealized losses, Total	(176)	(1)
Corporate debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of less than 12 months	65,329	24,203
Unrealized losses of less than 12 months	(207)	(30)
Fair value of 12 months or greater
Unrealized losses of 12 months or greater
Fair value, Total	65,329	24,203
Unrealized losses, Total	(207)	(30)
Mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of less than 12 months	26,216	10,048
Unrealized losses of less than 12 months	(310)	(44)
Fair value of 12 months or greater	2,306
Unrealized losses of 12 months or greater	(38)
Fair value, Total	28,522	10,048
Unrealized losses, Total	(348)	(44)
Other debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of less than 12 months	2,956
Unrealized losses of less than 12 months	(2)
Fair value of 12 months or greater
Unrealized losses of 12 months or greater
Fair value, Total	2,956
Unrealized losses, Total	(2)
Municipal bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of less than 12 months	17,076
Unrealized losses of less than 12 months	(99)
Fair value of 12 months or greater
Unrealized losses of 12 months or greater
Fair value, Total	17,076
Unrealized losses, Total	$ (99)