| Property and Equipment - Depreciation and Amortization Expense (Details) - USD ($) | 3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
| Jan. 31, 2020 | Jan. 31, 2019 | Jan. 31, 2020 | Jan. 31, 2019 | |
| Property, Plant and Equipment [Abstract] | 听 | 听 | 听 | 听 | 
| Depreciation and amortization expense | $ 364,504 | $ 263,045 | $ 1,012,548 | $ 703,886 | 
| Software amortization expense | $ 265,146 | $ 178,459 | $ 728,395 | $ 482,153 | 
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- Definition Amount of expense for amortization of capitalized computer software costs. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- References No definition available. 
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