Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Weighted-average period over which cost not yet recognized is expected to be recognized for 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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Amount of cost to be recognized for option under share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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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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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Equity incentive plan (Narrative) (Details) - USD ($)					6 Months Ended
Equity incentive plan (Narrative) (Details) - USD ($)	Mar. 04, 2019	May 03, 2018	Nov. 10, 2016	Sep. 04, 2014	Apr. 30, 2021	Apr. 30, 2020
Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance					442,060
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Plan term	10 years	10 years	10 years	10 years
Vesting term	5 years	5 years	5 years
Options granted during period	5,000	38,000	38,000	246,000
Options granted during period, price per share	$ 15.00	$ 15.50	$ 21.00	$ 18.45
Compensation expense related to stock options					$ 24,000	$ 24,000
Unrecognized compensation cost					$ 48,000
Unrecognized compensation cost, recognition period					1 year 9 months 18 days
Aggregate intrinsic value of options expected to vest					$ 115,000
Aggregate intrinsic value of options exercisable					$ 47,000