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Schedule of Stock Option Activity (Details)	3 Months Ended
	Jul. 31, 2021 $ / shares shares
Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Underlying Options Outstanding, Beginning | shares	516,827
Weighted Average Exercise Price, Beginning Balance | $ / shares	$ 3.89
Weighted Average Remaining Contractual Term (In Years), Beginning	8 years 3 months 18 days
Shares Underlying Options Outstanding, Granted | shares
Weighted Average Exercise Price, Granted | $ / shares
Shares Underlying Options Outstanding, Exercised | shares
Weighted Average Exercise Price, Exercised | $ / shares
Shares Underlying Options Outstanding, Cancelled/forfeited | shares	(3,681)
Weighted Average Exercise Price, Cancelled/forfeited | $ / shares	$ 13.81
Shares Underlying Options Outstanding, Ending | shares	513,146
Weighted Average Exercise Price, Ending Balance | $ / shares	$ 3.81
Weighted Average Remaining Contractual Term (In Years), Ending	8 years 8 months 12 days
Shares Underlying Options Outstanding, Exercisable at Ending | shares	247,954
Weighted Average Exercise Price, Exercisable at Ending | $ / shares	$ 4.92
Weighted Average Remaining Contractual Term (In Years), Exercisable at Ending	8 years
Performance Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Underlying Options Outstanding, Beginning | shares	424,790
Weighted Average Exercise Price, Beginning Balance | $ / shares	$ 2.57
Weighted Average Remaining Contractual Term (In Years), Beginning	8 years 8 months 12 days
Shares Underlying Options Outstanding, Granted | shares
Weighted Average Exercise Price, Granted | $ / shares
Shares Underlying Options Outstanding, Exercised | shares
Weighted Average Exercise Price, Exercised | $ / shares
Shares Underlying Options Outstanding, Cancelled/forfeited | shares	(6,767)
Weighted Average Exercise Price, Cancelled/forfeited | $ / shares	$ 2.93
Shares Underlying Options Outstanding, Ending | shares	418,023
Weighted Average Exercise Price, Ending Balance | $ / shares	$ 2.56
Weighted Average Remaining Contractual Term (In Years), Ending	9 years 3 months 18 days
Shares Underlying Options Outstanding, Exercisable at Ending | shares	40,668
Weighted Average Exercise Price, Exercisable at Ending | $ / shares	$ 1.05
Weighted Average Remaining Contractual Term (In Years), Exercisable at Ending	8 years 6 months

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Gross number of share options (or share units) granted during the period.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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