| Income Taxes - Narrative (Details) - USD ($) | Apr. 30, 2022 | Apr. 30, 2021 | Apr. 30, 2020 | 
|---|---|---|---|
| Income Tax Contingency [Line Items] | Ìý | Ìý | Ìý | 
| Valuation allowance | $ 19,382,895 | $ 14,776,048 | $ 12,399,948 | 
| Net operating loss carry forwards | 69,700,000 | Ìý | Ìý | 
| Operating loss carryforwards subject to expiration | 28,200,000 | Ìý | Ìý | 
| Tax Year 2013 to 2021 | Ìý | Ìý | Ìý | 
| Income Tax Contingency [Line Items] | Ìý | Ìý | Ìý | 
| Reserve for estimate of foreign income tax liability | 300,000 | Ìý | Ìý | 
| Tax Year 2022 | Ìý | Ìý | Ìý | 
| Income Tax Contingency [Line Items] | Ìý | Ìý | Ìý | 
| Reserve for estimate of foreign income tax liability | $ 100,000 | Ìý | Ìý | 
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards that are subject to expiration dates. No definition available. 
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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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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
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- Definition Amount recognized for uncertainty in income taxes classified as noncurrent. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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