Investments - Summary of Available for Sale Investments (Detail) - USD ($)	Oct. 02, 2020	Sep. 27, 2019
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 203,518,000	$ 101,224,000
Gross Unrealized Holding Gains	540,000	113,000
Gross Unrealized Holding Losses	(347,000)	(111,000)
Aggregate Fair Value	203,711,000	101,226,000
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	68,605,000	29,578,000
Gross Unrealized Holding Gains	348,000	112,000
Gross Unrealized Holding Losses	(333,000)	(93,000)
Aggregate Fair Value	68,620,000	29,597,000
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	134,913,000	71,646,000
Gross Unrealized Holding Gains	192,000	1,000
Gross Unrealized Holding Losses	(14,000)	(18,000)
Aggregate Fair Value	$ 135,091,000	$ 71,629,000

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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-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
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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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