Ë¿¹ÏÊÓƵ

Quarterly report pursuant to Section 13 or 15(d)

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

v3.20.4
Stockholders' Equity - Schedule of All Options and Exercisable Options (Details) - $ / shares
 6 Months Ended
Oct. 31, 2020
Oct. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Ìý Ìý
Outstanding (in shares) 1,744,354 3,021,131
Exercisable (in shares) 1,439,330 Ìý
$1.57 to $2.10 Ìý Ìý
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Ìý Ìý
Minimum exercise price (in dollars per share) $ 1.57 Ìý
Maximum exercise price (in dollars per share) 2.10 Ìý
Weighted average exercise price (in dollars per share) $ 1.86 Ìý
Outstanding (in shares) 35,141 Ìý
Weighted average exercise price (in dollars per share) $ 1.86 Ìý
Weighted average remaining life in years 5 months 8 days Ìý
Exercisable (in shares) 35,141 Ìý
$2.28 to $2.76 Ìý Ìý
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Ìý Ìý
Minimum exercise price (in dollars per share) $ 2.28 Ìý
Maximum exercise price (in dollars per share) 2.76 Ìý
Weighted average exercise price (in dollars per share) $ 2.34 Ìý
Outstanding (in shares) 96,573 Ìý
Weighted average exercise price (in dollars per share) $ 2.34 Ìý
Weighted average remaining life in years 3 months Ìý
Exercisable (in shares) 96,573 Ìý
$3.24 to $4.38 Ìý Ìý
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Ìý Ìý
Minimum exercise price (in dollars per share) $ 3.24 Ìý
Maximum exercise price (in dollars per share) 4.38 Ìý
Weighted average exercise price (in dollars per share) $ 3.90 Ìý
Outstanding (in shares) 262,658 Ìý
Weighted average exercise price (in dollars per share) $ 3.87 Ìý
Weighted average remaining life in years 11 months 12 days Ìý
Exercisable (in shares) 220,657 Ìý
$4.50 to $5.20 Ìý Ìý
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Ìý Ìý
Minimum exercise price (in dollars per share) $ 4.50 Ìý
Maximum exercise price (in dollars per share) 5.20 Ìý
Weighted average exercise price (in dollars per share) $ 4.93 Ìý
Outstanding (in shares) 650,808 Ìý
Weighted average exercise price (in dollars per share) $ 4.91 Ìý
Weighted average remaining life in years 1 year 9 months Ìý
Exercisable (in shares) 540,896 Ìý
$5.95 to $6.28 Ìý Ìý
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Ìý Ìý
Minimum exercise price (in dollars per share) $ 5.95 Ìý
Maximum exercise price (in dollars per share) 6.28 Ìý
Weighted average exercise price (in dollars per share) $ 6.10 Ìý
Outstanding (in shares) 67,000 Ìý
Weighted average exercise price (in dollars per share) $ 6.10 Ìý
Weighted average remaining life in years 1 year 8 months 19 days Ìý
Exercisable (in shares) 67,000 Ìý
$7.17 to $7.55 Ìý Ìý
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Ìý Ìý
Minimum exercise price (in dollars per share) $ 7.17 Ìý
Maximum exercise price (in dollars per share) 7.55 Ìý
Weighted average exercise price (in dollars per share) $ 7.45 Ìý
Outstanding (in shares) 474,425 Ìý
Weighted average exercise price (in dollars per share) $ 7.43 Ìý
Weighted average remaining life in years 2 years 10 months 13 days Ìý
Exercisable (in shares) 329,175 Ìý
$8.57 to $9.07 Ìý Ìý
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Ìý Ìý
Minimum exercise price (in dollars per share) $ 8.57 Ìý
Maximum exercise price (in dollars per share) 9.07 Ìý
Weighted average exercise price (in dollars per share) $ 8.98 Ìý
Outstanding (in shares) 157,749 Ìý
Weighted average exercise price (in dollars per share) $ 9.00 Ìý
Weighted average remaining life in years 2 years 2 months 4 days Ìý
Exercisable (in shares) 149,888 Ìý