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Share-Based Payments - Narrative (Details) - $ / shares | 3 Months Ended
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Jul. 31, 2021 | Jul. 31, 2020
Share-based Payment Arrangement [Abstract] |  |
Weighted-average grant date fair value (in usd per share) | $ 5.33 | $ 9.85

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- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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