| Schedule of Weighted Average Number of Shares [Table Text Block] |
| | | Years Ended April 30, | | | | 2019 | | 2018 | | 2017 | | | | | | | | | | Weighted average shares outstanding-basic | | | 6,810,879 | | | | 7,232,014 | | | | 7,854,238 | | | Dilutive options and restricted stock | | | 260,889 | | | | 209,344 | | | | 256,539 | | | | | | | | | | | | | | | | | Weighted average shares outstanding-diluted | | | 7,071,768 | | | | 7,441,358 | | | | 8,110,777 | | | | | | | | | | | | | | | | | Antidilutive securities not included: | | | | | | | | | | | | | | Options | | | 60,000 | | | | 229,000 | | | | 359,250 | | |