Income Taxes - Summary of Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2021	Aug. 01, 2020
Income Taxes Valuation Allowance [Roll Forward]
Beginning of year valuation allowance	$ 43,153	$ 0
Valuation allowance charged / (credited) to expense	40,995	43,153
Valuation allowance charged / (credited) to other accounts	(6,544)	0
End of year valuation allowance	$ 77,604	$ 43,153