Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity (Schedule of All Options and Exercisable Options) (Details)

v3.19.2
Stockholders' Equity (Schedule of All Options and Exercisable Options) (Details)
12 Months Ended
Apr. 30, 2019
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
ALL OPTIONS, Outstanding No. of Options | shares 3,409,154
EXERCISABLE OPTIONS, Exercisable No. of Options | shares 2,244,861
$1.57 to $2.10 [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
ALL OPTIONS, Exercise Price Lower Range $ 1.57
ALL OPTIONS, Exercise Price Upper Range 2.10
ALL OPTIONS, Weighted Average Exercise Price $ 1.96
ALL OPTIONS, Outstanding No. of Options | shares 919,390
EXERCISABLE OPTIONS, Weighted Average Exercise Price $ 1.96
EXERCISABLE OPTIONS, Weighted Average Remaining Life In Years 2 years 22 days
EXERCISABLE OPTIONS, Exercisable No. of Options | shares 919,390
$2.28 to $2.76 [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
ALL OPTIONS, Exercise Price Lower Range $ 2.28
ALL OPTIONS, Exercise Price Upper Range 2.76
ALL OPTIONS, Weighted Average Exercise Price $ 2.32
ALL OPTIONS, Outstanding No. of Options | shares 471,081
EXERCISABLE OPTIONS, Weighted Average Exercise Price $ 2.32
EXERCISABLE OPTIONS, Weighted Average Remaining Life In Years 1 year 5 months 5 days
EXERCISABLE OPTIONS, Exercisable No. of Options | shares 471,081
$3.24 to $4.38 [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
ALL OPTIONS, Exercise Price Lower Range $ 3.24
ALL OPTIONS, Exercise Price Upper Range 4.38
ALL OPTIONS, Weighted Average Exercise Price $ 4.20
ALL OPTIONS, Outstanding No. of Options | shares 333,224
EXERCISABLE OPTIONS, Weighted Average Exercise Price $ 3.86
EXERCISABLE OPTIONS, Weighted Average Remaining Life In Years 2 years 4 months 20 days
EXERCISABLE OPTIONS, Exercisable No. of Options | shares 261,834
$4.50 to $5.20 [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
ALL OPTIONS, Exercise Price Lower Range $ 4.50
ALL OPTIONS, Exercise Price Upper Range 5.20
ALL OPTIONS, Weighted Average Exercise Price $ 4.96
ALL OPTIONS, Outstanding No. of Options | shares 718,292
EXERCISABLE OPTIONS, Weighted Average Exercise Price $ 4.90
EXERCISABLE OPTIONS, Weighted Average Remaining Life In Years 3 years 15 days
EXERCISABLE OPTIONS, Exercisable No. of Options | shares 336,833
$5.95 to $6.28 [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
ALL OPTIONS, Exercise Price Lower Range $ 5.95
ALL OPTIONS, Exercise Price Upper Range 6.28
ALL OPTIONS, Weighted Average Exercise Price $ 6.07
ALL OPTIONS, Outstanding No. of Options | shares 80,417
EXERCISABLE OPTIONS, Weighted Average Exercise Price $ 6.13
EXERCISABLE OPTIONS, Weighted Average Remaining Life In Years 3 years 2 months 5 days
EXERCISABLE OPTIONS, Exercisable No. of Options | shares 36,806
$7.17 to $7.55 [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
ALL OPTIONS, Exercise Price Lower Range $ 7.17
ALL OPTIONS, Exercise Price Upper Range 7.55
ALL OPTIONS, Weighted Average Exercise Price $ 7.39
ALL OPTIONS, Outstanding No. of Options | shares 662,417
EXERCISABLE OPTIONS, Weighted Average Exercise Price $ 7.51
EXERCISABLE OPTIONS, Weighted Average Remaining Life In Years 4 years 2 months 1 day
EXERCISABLE OPTIONS, Exercisable No. of Options | shares 144,139
$8.57 to $9.07 [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
ALL OPTIONS, Exercise Price Lower Range $ 8.57
ALL OPTIONS, Exercise Price Upper Range 9.07
ALL OPTIONS, Weighted Average Exercise Price $ 8.97
ALL OPTIONS, Outstanding No. of Options | shares 224,333
EXERCISABLE OPTIONS, Weighted Average Exercise Price $ 8.97
EXERCISABLE OPTIONS, Weighted Average Remaining Life In Years 3 years 8 months 9 days
EXERCISABLE OPTIONS, Exercisable No. of Options | shares 74,778