| SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) | 12 Months Ended | |
|---|---|---|
| Apr. 30, 2021 | Apr. 30, 2020 | |
| SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract] | ||
| Deferred tax assets, beginning balance | $ 15,528,958 | $ 14,187,771 | 
| Additions charged to costs and expenses | 0 | 0 | 
| Charged to other accounts | 969,241 | 1,341,187 | 
| Deductions | 0 | 0 | 
| Deferred tax assets, ending balance | $ 16,498,199 | $ 15,528,958 | 
| X | ||||||||||
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- Definition Deferred Tax Assets, Valuation Allowance, charged to costs and expenses No definition available. 
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| X | ||||||||||
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- Definition Deferred Tax Assets, Valuation Allowance, deductions No definition available. 
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| X | ||||||||||
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- References No definition available. 
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| X | ||||||||||
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- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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| X | ||||||||||
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- Definition Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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