Investments and Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Jun. 28, 2014	Mar. 29, 2014
Available-for-Sale securities
Cost	$ 143,022	$ 184,014
Gross Unrealized Gains	1	1
Gross Unrealized Losses	(1)
Estimated fair value	143,022	184,015
U.S. government/agency securities [Member]
Available-for-Sale securities
Cost	102,064	133,064
Gross Unrealized Gains	1	1
Gross Unrealized Losses	(1)
Estimated fair value	102,064	133,065
Auction Rate Securities [Member]
Available-for-Sale securities
Cost	2,150	2,150
Estimated fair value	2,150	2,150
Money Market Funds [Member]
Available-for-Sale securities
Cost	38,808	48,800
Estimated fair value	$ 38,808	$ 48,800