Investments - Unrealized Loss (Details) - USD ($) $ in Thousands	Jul. 01, 2018	Apr. 01, 2018
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less Than 12 Months	$ 117,617	$ 118,225
Unrealized Loss, Less Than 12 Months	(1,683)	(1,635)
Fair Value, 12 Months or Greater	63,248	63,384
Unrealized Loss, 12 Months or Greater	(1,002)	(1,085)
Fair Value, Total	180,865	181,609
Unrealized Loss, Total	(2,685)	(2,720)
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less Than 12 Months	79,242	78,726
Unrealized Loss, Less Than 12 Months	(1,358)	(1,324)
Fair Value, 12 Months or Greater	23,324	23,286
Unrealized Loss, 12 Months or Greater	(332)	(380)
Fair Value, Total	102,566	102,012
Unrealized Loss, Total	(1,690)	(1,704)
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less Than 12 Months	13,027	14,147
Unrealized Loss, Less Than 12 Months	(77)	(90)
Fair Value, 12 Months or Greater	2,340	2,540
Unrealized Loss, 12 Months or Greater	(16)	(20)
Fair Value, Total	15,367	16,687
Unrealized Loss, Total	(93)	(110)
U.S. government treasuries and agencies securities
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less Than 12 Months	25,348	25,352
Unrealized Loss, Less Than 12 Months	(248)	(221)
Fair Value, 12 Months or Greater	34,940	34,920
Unrealized Loss, 12 Months or Greater	(648)	(673)
Fair Value, Total	60,288	60,272
Unrealized Loss, Total	(896)	(894)
International government bonds
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less Than 12 Months		0
Unrealized Loss, Less Than 12 Months		0
Fair Value, 12 Months or Greater	2,644	2,638
Unrealized Loss, 12 Months or Greater	(6)	(12)
Fair Value, Total	2,644	2,638
Unrealized Loss, Total	$ (6)	$ (12)