Investments and Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Dec. 28, 2013	Mar. 30, 2013
Available-for-Sale securities
Cost	$ 128,999	$ 106,466
Gross Unrealized Gains	4	3
Gross Unrealized Losses	0	(4)
Estimated fair value	129,003	106,465
U.S. government/agency securities [Member]
Available-for-Sale securities
Cost	88,055	77,988
Gross Unrealized Gains	4	3
Gross Unrealized Losses	0	(4)
Estimated fair value	88,059	77,987
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	38,794	26,328
Estimated fair value	$ 38,794	$ 26,328