Net Loss Per Share Attributable to Common Stockholders - Computation of basic and diluted earnings per share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Oct. 03, 2020	Sep. 28, 2019	Sep. 29, 2018
Numerator:
Net loss attributable to common stockholders - basic and diluted	$ (20,115)	$ (4,766)	$ (15,604)
Denominator:
Weighted-average shares of common stock—basic and diluted (in shares)	109,807,154	103,783,006	65,706,215
Net loss per share attributable to common stockholders:
Net loss per share attributable to common stockholders - basic and diluted (in dollars per share)	$ (0.18)	$ (0.05)	$ (0.24)