Amortized Cost and Fair Value of Available-for-Sale Investments (Detail) - USD ($) $ in Thousands	Dec. 25, 2021	Dec. 26, 2020
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 171,449	$ 119,013
Gross Unrealized Gains	1,456	3,676
Gross Unrealized Losses	1,312	98
Fair Value	171,593	122,591
Money market investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	8,750	17,867
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Value	8,750	17,867
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	22,441	567
Gross Unrealized Gains	0
Gross Unrealized Losses	346	26
Fair Value	22,095	541
Corporate bonds and direct obligations of government agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	137,916	98,241
Gross Unrealized Gains	1,406	3,551
Gross Unrealized Losses	966	72
Fair Value	138,356	101,720
U.S. Treasury obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,342	2,338
Gross Unrealized Gains	50	125
Gross Unrealized Losses	0
Fair Value	$ 2,392	$ 2,463

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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