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Summary of Significant Accounting Policies (Details Narrative) - USD ($) | 3 Months Ended | 9 Months Ended |  |
--- | --- | --- | --- | ---
Jan. 31, 2021 | Jan. 31, 2020 | Jan. 31, 2021 | Jan. 31, 2020 | Aug. 31, 2020 | Apr. 30, 2020
Cash and cash equivalents | $ 79,801,000 |  | $ 79,801,000 |  |  | $ 10,002,000
Revenue remaining performance obligation | 500,000 |  | $ 500,000 |  |  |
Revenue remaining performance obligation, percentage |  |  | 89.00% |  |  |
Performance obligation revenue of next twelve months | $ 400,000 |  | $ 400,000 |  |  |
Antidilutive securities excluded from computation of earnings per share, shares | 5,221,258 | 5,565,462 | 5,221,258 | 5,565,462 |  |
Santander Bank, N.A. [Member] | Letter 2 [Member] |  |  |  |  |  |
Letters of credit issued, amount | $ 64,547 |  | $ 64,547 |  |  |
Santander Bank, N.A. [Member] | Letter 2 [Member] | August 2020 [Member] |  |  |  |  |  |
Letters of credit outstanding, amount |  |  |  |  | $ 322,734 |
Foreign Financial Institutions [Member] |  |  |  |  |  |
Cash and cash equivalents | 300,000 |  | 300,000 |  |  |
Restricted Cash and Security Agreements [Member] | Santander Bank, N.A. [Member] | Letter 1 [Member] |  |  |  |  |  |
Letters of credit outstanding, amount | 125,690 |  | $ 125,690 |  |  |
Line of credit expiration period |  |  | May 31, 2021 |  |  |
Restricted Cash and Security Agreements [Member] | Santander Bank, N.A. [Member] | Letter 2 [Member] |  |  |  |  |  |
Letters of credit outstanding, amount | $ 645,467 |  | $ 645,467 |  |  |

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