Quarterly report pursuant to Section 13 or 15(d)

Significant Accounting Policies (Narrative) (Details)

v3.8.0.1
Significant Accounting Policies (Narrative) (Details) - USD ($)
6 Months Ended
Oct. 31, 2017
Oct. 31, 2016
Apr. 30, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Cash insured by FDIC $ 250,000    
Amount of cash balance uninsured by FDIC $ 5,486,370   $ 2,687,461
Employee Stock Option [Member]      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Antidilutive securities 2,669,286 1,849,832  
Warrant [Member]      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Antidilutive securities 1,001,557 934,555  
Convertible Debt [Member]      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Antidilutive securities 4,167 75,596  
Convertible debt $ 50,000 $ 350,000  
Sales Revenue, Net [Member] | Non-US [Member]      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Percentage of revenues from students outside the United States 2.20%