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Quarterly report pursuant to Section 13 or 15(d)

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

v3.7.0.1
Stockholders' Equity (Schedule of Stock Options Activity) (Details)
 9 Months Ended
Jan. 31, 2017
USD ($)
$ / shares
shares
Stock Incentive Plan and Stock Option Grants to Employees and Directors [Member]  
Number of Shares  
Balance outstanding | shares 1,494,259
Granted | shares 538,333
Forfeited | shares (85,361)
Expired | shares
Balance outstanding | shares 1,947,231
Exercisable | shares 1,891,540
Weighted Average Exercise Price  
Balance outstanding $ 2.76
Granted 2.40
Exercised
Forfeited 3.72
Expired
Balance outstanding 2.28
Exercisable $ 2.28
Beginning balance outstanding 7 months 6 days
Granted 4 years 5 months
Forfeited 1 year 10 months 24 days
Ending balance outstanding 3 years 1 month 2 days
Exercisable 1 year 10 months 10 days
Aggregate Intrinsic Value  
Balance outstanding | $ $ 2,020,711
Granted | $ 694,390
Forfeited | $
Balance outstanding | $ 2,715,101
Exercisable | $ $ 1,375,198
Stock Option Grants To Non Employees [Member]  
Number of Shares  
Balance outstanding | shares 16,250
Granted | shares
Exercised | shares
Forfeited | shares
Expired | shares
Balance outstanding | shares 16,250
Exercisable | shares 16,250
Weighted Average Exercise Price  
Balance outstanding $ 3.48
Granted
Exercised
Forfeited
Expired
Balance outstanding 3.48
Exercisable $ 3.48
Beginning balance outstanding 2 months 12 days
Ending balance outstanding 2 months 12 days
Exercisable 2 months 12 days
Aggregate Intrinsic Value  
Balance outstanding | $ $ 8,550
Granted | $
Forfeited | $
Balance outstanding | $ 8,550
Exercisable | $ $ 8,550