Balance Sheet Components - Change in deferred revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 02, 2021	Dec. 28, 2019
Contract with Customer, Liability [Roll Forward]
Deferred revenue, beginning of period	$ 62,389	$ 56,449
Recognition of revenue included in beginning of period deferred revenue	(3,357)	(3,238)
Revenue deferred, net of revenue recognized on contracts in the respective period	9,809	8,435
Deferred revenue, end of period	$ 68,841	$ 61,646