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Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs (Details) - USD ($) $ in Thousands | 3 Months Ended
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Jul. 31, 2021 | Jul. 31, 2020
Total share-based compensation expense | $ 390 | $ 116
Engineering and Product Development [Member] |  |
Total share-based compensation expense | 217 | 37
Selling, General and Administrative Expenses [Member] |  |
Total share-based compensation expense | $ 173 | $ 79

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- Definition Amount of noncash expense for share-based payment arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585 + Details
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- Details
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Data Type: | na
Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
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Balance Type: |
Period Type: |