Balance Sheet Components - Finite-lived intangible assets, future amortization expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 02, 2021	Oct. 03, 2020
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross carrying amount	$ 7,914
Accumulated amortization	(2,039)
Finite-lived intangible assets, net carrying value	5,875
Intangible assets, gross carrying amount (excluding goodwill)	28,014
Intangible assets, net carrying value (excluding goodwill)	$ 25,975	$ 26,394
Weighted-average remaining life	3 years 3 months 18 days
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Remainder of fiscal 2021	$ 1,478
2022	1,955
2023	1,253
2024	1,020
2025	169
2026 and thereafter	0
Finite-lived intangible assets, net carrying value	5,875
In progress research and development
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets (excluding goodwill)	20,100
Technology
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross carrying amount	7,875
Accumulated amortization	(2,018)
Finite-lived intangible assets, net carrying value	$ 5,857
Weighted-average remaining life	3 years 3 months 21 days
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Finite-lived intangible assets, net carrying value	$ 5,857
Other
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross carrying amount	39
Accumulated amortization	(21)
Finite-lived intangible assets, net carrying value	$ 18
Weighted-average remaining life	11 months 1 day
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Finite-lived intangible assets, net carrying value	$ 18