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Income Taxes - Additional Information (Details) - USD ($)
$ in Millions
12 Months Ended
Aug. 03, 2019
Jul. 28, 2018
Jul. 29, 2017
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]      
Blended U.S. statutory rate 21.00% 27.00% 35.00%
Increase of liability for uncertain tax positions that impact current and future tax expense $ 7.7    
Lapses of applicable statutes of limitations      
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]      
Expected decrease of unrecognized tax benefits 0.9    
Federal      
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]      
Research and development tax credit carryforwards 3.5    
California      
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]      
Research and development tax credit carryforwards $ 5.2 $ 1.5  
State      
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]      
Operating loss carryforwards   $ 0.2