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Stock-Based Compensation - Fair value assumptions used in Black-Scholes option-pricing (Details)
9 Months Ended
Apr. 30, 2020
$ / shares
Time to expiration 5 years
Estimated volatility 153.40%
Expected dividend 0.00%
Minimum [Member]  
Exercise price $ 1.44
Risk-free interest rate 1.51%
Stock price at period end date $ 1.44
Maximum [Member]  
Exercise price $ 1.49
Risk-free interest rate 1.59%
Stock price at period end date $ 1.49