Investments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Jun. 29, 2014	Mar. 30, 2014
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	$ 359,819	$ 362,604
U.S. government treasuries and agencies securities
Schedule of Available-for-sale Securities [Line Items]
Cost	110,656	112,268
Gross Unrealized Gains	175	76
Gross Unrealized Losses	(17)	(91)
Estimated Fair Value	110,814	112,253
Money market funds
Schedule of Available-for-sale Securities [Line Items]
Cost	42,737	53,430
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	42,737	53,430
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Cost	24,989	22,330
Gross Unrealized Gains	31	11
Gross Unrealized Losses	(1)	(9)
Estimated Fair Value	25,019	22,332
Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Cost	199,375	199,598
Gross Unrealized Gains	456	335
Gross Unrealized Losses	(48)	(127)
Estimated Fair Value	199,783	199,806
International government bonds
Schedule of Available-for-sale Securities [Line Items]
Cost	1,013	3,023
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(7)	(9)
Estimated Fair Value	1,006	3,014
Corporate commercial paper
Schedule of Available-for-sale Securities [Line Items]
Cost	5,295	6,246
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	5,295	6,246
Bank deposits
Schedule of Available-for-sale Securities [Line Items]
Cost	13,934	18,538
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	13,934	18,538
Repurchase agreements
Schedule of Available-for-sale Securities [Line Items]
Cost	164	46
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	164	46
Municipal bonds
Schedule of Available-for-sale Securities [Line Items]
Cost	10,065	9,196
Gross Unrealized Gains	48	32
Gross Unrealized Losses	(6)	(18)
Estimated Fair Value	10,107	9,210
Total available-for-sale investments
Schedule of Available-for-sale Securities [Line Items]
Cost	408,228	424,675
Gross Unrealized Gains	710	454
Gross Unrealized Losses	(79)	(254)
Estimated Fair Value	408,859	424,875
Less amounts classified as cash equivalents
Schedule of Available-for-sale Securities [Line Items]
Cost	49,040	62,271
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	49,040	62,271
Short-term investments
Schedule of Available-for-sale Securities [Line Items]
Cost	359,188	362,404
Gross Unrealized Gains	710	454
Gross Unrealized Losses	(79)	(254)
Estimated Fair Value	$ 359,819	$ 362,604