Cash, Cash Equivalents, and Investments - Gross Unrealized Losses and Fair Values for Available-for-Sale Investments (Detail) $ in Thousands	Apr. 01, 2018 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	$ 388,798
Unrealized losses, less than 12 months	(1,736)
Fair value, 12 months or greater	77,550
Unrealized losses, 12 months or greater	(558)
Total fair value	466,348
Total unrealized losses	(2,294)
Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	172,162
Unrealized losses, less than 12 months	(812)
Fair value, 12 months or greater	23,693
Unrealized losses, 12 months or greater	(292)
Total fair value	195,855
Total unrealized losses	(1,104)
Treasury bills
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	96,209
Unrealized losses, less than 12 months	(277)
Fair value, 12 months or greater	42,487
Unrealized losses, 12 months or greater	(187)
Total fair value	138,696
Total unrealized losses	(464)
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	112,632
Unrealized losses, less than 12 months	(614)
Fair value, 12 months or greater	2,640
Unrealized losses, 12 months or greater	(10)
Total fair value	115,272
Total unrealized losses	(624)
Sovereign bonds
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	3,599
Unrealized losses, less than 12 months	(9)
Fair value, 12 months or greater	8,730
Unrealized losses, 12 months or greater	(69)
Total fair value	12,329
Total unrealized losses	(78)
Municipal bonds
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	4,196
Unrealized losses, less than 12 months	(24)
Fair value, 12 months or greater	0
Unrealized losses, 12 months or greater	0
Total fair value	4,196
Total unrealized losses	(24)
Agency bonds
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	0
Unrealized losses, less than 12 months	0
Fair value, 12 months or greater	0
Unrealized losses, 12 months or greater	0
Total fair value	0
Total unrealized losses	$ 0