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Schedule of Share-based Payment Award, Stock Options, Valuation Assumption (Details)	6 Months Ended
	Oct. 31, 2021	Oct. 31, 2020
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Dividend rate	0.00%	0.00%
Expected life (in years)	1 month 6 days
Expected volatility	122.20%	139.10%
Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Risk-free interest rate	0.06%	0.12%
Expected life (in years)		9 months 18 days
Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Risk-free interest rate	0.08%	0.13%
Expected life (in years)		1 year 1 month 6 days

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

+ 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 (f)(2)(iii)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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