Stock-Based Compensation - Stock-based compensation expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 03, 2020	Sep. 28, 2019	Sep. 29, 2018
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 57,610	$ 46,575	$ 38,645
Cost of revenue
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	1,106	985	198
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	23,439	17,643	13,960
Sales and marketing
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	14,359	12,965	15,885
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 18,706	$ 14,982	$ 8,602