Schedule of Unrealized Loss on Available-for-Sale Investments (Detail) - USD ($) $ in Thousands	Jun. 26, 2021	Dec. 26, 2020
Debt Securities, Available-for-sale [Line Items]
Available-for-sale investments with unrealized losses, Less than 12 months, Fair Value		$ 3,222
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss		98
Available-for-sale investments with unrealized losses, Fair Value, Total		3,222
Available-for-sale investments with unrealized losses, Unrealized Loss, Total		98
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale investments with unrealized losses, Less than 12 months, Fair Value		541
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss		26
Available-for-sale investments with unrealized losses, Fair Value, Total		541
Available-for-sale investments with unrealized losses, Unrealized Loss, Total		26
Corporate bonds and direct obligations of government agencies
Debt Securities, Available-for-sale [Line Items]
Available-for-sale investments with unrealized losses, Less than 12 months, Fair Value	$ 52,720	2,681
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss	238	72
Available-for-sale investments with unrealized losses, Fair Value, Total	52,720	2,681
Available-for-sale investments with unrealized losses, Unrealized Loss, Total	$ 238	$ 72

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27337-111563

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This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities.

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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for less than twelve months.

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