Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Schedule of Assumptions Used to Calculate Fair Value of Stock Based Compensation (Details)

v3.19.2
Stock-Based Compensation - Schedule of Assumptions Used to Calculate Fair Value of Stock Based Compensation (Details)
9 Months Ended
Apr. 30, 2019
Apr. 30, 2018
Risk-free interest rate, minimum 2.31% 1.66%
Risk-free interest rate, maximum 3.09% 2.81%
Volatility, minimum 72.88% 73.30%
Volatility, maximum 82.77% 92.00%
Dividend yield 0.00% 0.00%
Minimum [Member]    
Expected term (years) 5 years 5 years
Maximum [Member]    
Expected term (years) 6 years 6 months 6 years 6 months