| Leases - Schedule of Balance Sheet Information Related to Leases (Details) - USD ($) | Jul. 31, 2020 | Apr. 30, 2020 | May 01, 2019 | 
|---|---|---|---|
| Operating leases | 听 | 听 | 听 | 
| Operating lease obligations, current portion | $ 1,542,754 | $ 1,683,252 | 听 | 
| Operating lease liabilities, long-term | 6,677,566 | $ 5,685,335 | 听 | 
| Present value of operating lease obligations | $ 8,220,320 | 听 | $ 8,000,000 | 
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- References No definition available. 
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease, classified as current. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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| X | ||||||||||
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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