Income Taxes - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2021	Aug. 01, 2020
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Increase of liability for uncertain tax positions that impact current and future tax expense	$ 4.0
Valuation allowance charged / (credited) to expense	34.5	$ 43.2
Lapses of applicable statutes of limitations
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Expected decrease of unrecognized tax benefits	2.2
Federal
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Research and development tax credit carryforwards	30.1	6.5
California
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Research and development tax credit carryforwards	17.0	$ 9.2
State
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Operating loss carryforwards	$ 142.0