Fair Market Value of Investments with Unrealized Losses Not Deemed to be Other-Than Temporarily Impaired (Detail) $ in Thousands	Mar. 30, 2019 USD ($)
Debt Securities, Available-for-sale [Line Items]
Unrealized Loss Position, Less than 12 Months, Fair Value	$ 0
Unrealized Loss Position, Less than 12 Months, Gross Unrealized Losses	0
Unrealized Loss Position, Greater than 12 Months, Fair Value	3,091
Unrealized Loss Position, Greater than 12 Months, Gross Unrealized Losses	9
Corporate bonds and medium-term notes
Debt Securities, Available-for-sale [Line Items]
Unrealized Loss Position, Less than 12 Months, Fair Value	0
Unrealized Loss Position, Less than 12 Months, Gross Unrealized Losses	0
Unrealized Loss Position, Greater than 12 Months, Fair Value	1,097
Unrealized Loss Position, Greater than 12 Months, Gross Unrealized Losses	4
U.S. treasury and agency securities
Debt Securities, Available-for-sale [Line Items]
Unrealized Loss Position, Less than 12 Months, Fair Value	0
Unrealized Loss Position, Less than 12 Months, Gross Unrealized Losses	0
Unrealized Loss Position, Greater than 12 Months, Fair Value	1,994
Unrealized Loss Position, Greater than 12 Months, Gross Unrealized Losses	$ 5