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EQUITY AWARD PLANS - ESPP (Details) - Employee Stock Purchase Plan
9 Months Ended
Apr. 30, 2019
Apr. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected term (in years) 25 days 22 days
Risk-free interest rate 2.50% 1.40%
Volatility 69.00% 49.80%
Dividend yield 0.00% 0.00%