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Stock-Based Compensation - Black-Scholes Option Pricing Model Assumptions (Details) - Options
12 Months Ended
Aug. 03, 2019
Jul. 28, 2018
Jul. 29, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Volatility, minimum 41.70% 41.40% 42.60%
Volatility, maximum 52.20% 43.50% 46.00%
Risk free interest rate, minimum 2.30% 1.90% 1.30%
Risk free interest rate, maximum 3.00% 3.00% 2.30%
Dividend yield 0.00% 0.00% 0.00%
Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected term (in years) 5 years 1 month 6 days 5 years 4 months 24 days 5 years 1 month 6 days
Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected term (in years) 6 years 6 months 6 years 7 months 6 days 7 years 8 months 12 days