Schedule of Share-based Compensation, Stock Options, Activity (Details) - $ / shares	3 Months Ended
Jul. 31, 2019	Jul. 31, 2018
Number of Options Outstanding at the beginning of period	616,449
Weighted Average Exercise Price per Share of Options Outstanding at the beginning of period	$ 2.27
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	0	7,500
Weighted Average Exercise Price per Share of Options Granted	$ 0
Number of Options Forfeited/Cancelled	(22,396)
Weighted Average Exercise Price per Share of Options Forfeited/Cancelled	$ 2.16
Number of Options Expired	(39,500)
Weighted Average Exercise Price per Share of Options Expired	$ 2.50
Number of Options Exercised	0	(35,500)
Weighted Average Exercise Price per Share of Options Exercised	$ 0
Number of Options Outstanding at the end of period	554,553
Weighted Average Exercise Price per Share of Options Outstanding at end of period	$ 2.25
Number of Options Exercisable at the end of period	212,397
Weighted Average Exercise Price per Share of Options Exercisable at end of period	$ 2.61
Number of Options Exercisable at the beginning of period	239,551
Weighted Average Exercise Price per Share of Options Exercisable at beginning of period	$ 2.58

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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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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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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Number of share options (or share units) exercised during the current period.

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