Short-Term Investments (Details) - USD ($)	Jan. 02, 2021	Oct. 03, 2020	Dec. 28, 2019
Schedule of Investments [Line Items]
Cash and cash equivalents, Cost Basis	$ 508,214,000	$ 440,258,000
Cash and cash equivalent, Unrealized Gains	0	0
Cash and cash equivalent, Unrealized Losses	0	0
Cash and cash equivalents	508,214,000	440,258,000	$ 349,592,000
Debt Securities, available-for-sale, accumulated gross unrealized gain (loss), before tax	100,000	100,000
Short-term investments:
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	35,257,000	35,311,000
Available-for-sale securities, Unrealized Gains	104,000	36,000
Available-for-sale securities, Unrealized Losses	0	(1,000)
Available-for-sale securities: Fair Value	35,361,000	35,346,000
Short-term investments: \| U.S. Treasury and agency obligations
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	35,257,000	35,311,000
Available-for-sale securities, Unrealized Gains	104,000	36,000
Available-for-sale securities, Unrealized Losses	0	(1,000)
Available-for-sale securities: Fair Value	$ 35,361,000	$ 35,346,000

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