Annual report pursuant to Section 13 and 15(d)

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

v3.10.0.1
Stockholders' Equity (Schedule of Stock Options Activity) (Details)
12 Months Ended
Apr. 30, 2018
USD ($)
$ / shares
shares
Number of Shares  
Exercised (136,563)
Stock Incentive Plan and Stock Option Grants to Employees and Directors [Member]  
Number of Shares  
Balance Outstanding, April 30, 2017 2,097,384
Granted 979,692
Exercised (136,563)
Forfeited (7,087)
Expired
Balance Outstanding, April 30, 2018 2,933,426
Exercisable, April 30, 2018 1,545,513
Weighted Average Exercise Price  
Balance Outstanding, April 30, 2017 | $ / shares $ 1.86
Granted | $ / shares 6.29
Exercised | $ / shares
Forfeited | $ / shares
Expired | $ / shares
Balance Outstanding, April 30, 2018 | $ / shares 3.58
Exercisable, April 30, 2018 | $ / shares $ 2.32
Weighted Average Remaining Contractual Term  
Balance Outstanding, April 30, 2017 2 years 8 months 12 days
Granted 4 years 6 months
Balance Outstanding, April 30, 2018 3 years 1 month 24 days
Exercisable, April 30, 2018 2 years 7 months 28 days
Aggregate Intrinsic Value  
Balance Outstanding, April 30, 2017 | $ $ 12,489,871
Granted | $ 1,610,110
Forfeited | $
Balance Outstanding, April 30, 2018 | $ 16,558,373
Exercisable, April 30, 2018 | $ $ 11,534,060