Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Schedule of Assumptions Used to Value Stock Options (Details)

v3.20.2
Stockholders' Equity - Schedule of Assumptions Used to Value Stock Options (Details) - Stock Incentive Plan and Stock Option Grants to Employees and Directors
12 Months Ended
Apr. 30, 2020
Apr. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected life (years) 3 years 6 months 3 years 6 months
Expected volatility 57.00% 50.10%
Risk-free interest rate 0.24% 2.63%
Dividend yield 0.00% 0.00%