Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.2
Stockholders' Equity (Schedule of Stock Options Activity) (Details)
 3 Months Ended
Jul. 31, 2019
USD ($)
$ / shares
shares
Number of Shares  
Balance Outstanding, July 31, 2019 3,237,840
Exercisable, July 31, 2019 2,057,324
Stock Incentive Plan and Stock Option Grants to Employees and Directors [Member]  
Number of Shares  
Balance Outstanding, April 30, 2019 3,408,154
Granted 30,000
Exercised (191,147)
Forfeited (9,167)
Expired
Balance Outstanding, July 31, 2019 3,237,840
Exercisable, July 31, 2019 2,057,324
Weighted Average Exercise Price  
Balance Outstanding, April 30, 2019 | $ / shares $ 4.44
Granted | $ / shares 4.12
Exercised | $ / shares 1.88
Forfeited | $ / shares 7.62
Expired | $ / shares
Balance Outstanding, July 31, 2019 | $ / shares 4.57
Exercisable, July 31, 2019 | $ / shares $ 3.50
Weighted Average Remaining Contractual Term  
Balance Outstanding, April 30, 2019 2 years 10 months 25 days
Balance Outstanding, July 31, 2019 2 years 10 months 25 days
Exercisable, July 31, 2019 2 years 9 months 14 days
Aggregate Intrinsic Value  
Balance Outstanding, April 30, 2019 | $ $ 6,880,644
Granted | $
Forfeited | $
Balance Outstanding, July 31, 2019 | $ 6,880,644
Exercisable, July 31, 2019 | $ $ 5,130,588