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Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity (Schedule of Stock Options Activity) (Details)

v3.7.0.1
Stockholders' Equity (Schedule of Stock Options Activity) (Details) - USD ($)
12 Months Ended
Apr. 30, 2017
Apr. 30, 2016
Stock Incentive Plan and Stock Option Grants to Employees and Directors [Member]    
Number of Shares    
Balance Outstanding, April 30, 2016 1,492,593  
Granted 671,666  
Exercised  
Forfeited (44,654)  
Expired (23,055)  
Balance Outstanding, April 30, 2017 2,096,550 1,492,593
Exercisable, April 30, 2017 1,963,217  
Weighted Average Exercise Price    
Balance Outstanding, April 30, 2016 $ 2.29  
Granted 2.74  
Exercised  
Forfeited 2.19  
Expired 4.13  
Balance Outstanding, April 30, 2017 2.42 $ 2.29
Exercisable, April 30, 2017 $ 2.83  
Weighted Average Remaining Contractual Term    
Balance Outstanding 3 years 1 month 2 days  
Granted 4 years 6 months  
Forfeited 1 year 6 months  
Exercisable, April 30, 2017 2 months 8 days  
Aggregate Intrinsic Value    
Balance Outstanding, April 30, 2016    
Balance Outstanding, April 30, 2017 $ 2,715,101  
Exercisable, April 30, 2017 $ 1,375,198  
Stock Option Grants To Non-Employees [Member]    
Number of Shares    
Balance Outstanding, April 30, 2016 16,250  
Granted  
Exercised  
Forfeited  
Expired (16,250)  
Balance Outstanding, April 30, 2017 16,250
Exercisable, April 30, 2017  
Weighted Average Exercise Price    
Balance Outstanding, April 30, 2016 $ 3.48  
Granted  
Exercised  
Forfeited  
Expired  
Balance Outstanding, April 30, 2017 $ 3.48
Exercisable, April 30, 2017  
Weighted Average Remaining Contractual Term    
Balance Outstanding   10 months 25 days
Aggregate Intrinsic Value    
Balance Outstanding, April 30, 2016  
Exercisable, April 30, 2017