Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity (Stock Options Narrative) (Details)

v3.10.0.1
Stockholders' Equity (Stock Options Narrative) (Details) - USD ($)
3 Months Ended
Jul. 19, 2018
Jul. 31, 2018
Jul. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Unrecognized compensation cost   $ 2,646,189  
Weighted average recognition period   2 years  
Stock-based compensation   $ 209,976  
Warrant [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options granted, exercise price    
Share issued in exercise of stock options   2,689  
Proceeds from stock options exercised   $ 7,817  
Chief Executive Officer [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options granted 200,000    
Options granted, exercise price $ 7.55    
Weighted average recognition period 5 years    
Chief Academic Officer [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options granted 180,000    
Options granted, exercise price $ 7.55    
Weighted average recognition period 5 years    
Chief Operating Officer [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options granted 180,000    
Options granted, exercise price $ 7.55    
Weighted average recognition period 5 years    
Board of directors [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options granted 560,000    
Weighted average recognition period 5 years    
Fair value of stock options granted $ 1,433,600    
Fair value of stock options per share $ 2.56    
Cashless Exercise of Stock Options [Member] | Warrant [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share issued in exercise of stock options   5,230  
Cashless exercise of stock option   8,334  
Equity Incentive Plan [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Equity Incentive Plan, shares authorized     3,500,000
Equity Incentive Plan, available shares remaining for issuance