Pension - Change in projected benefit obligation (Details) - Pension Plan - USD ($) $ in Thousands	12 Months Ended
Apr. 30, 2025	Apr. 30, 2024
Pension
Pension benefit obligation balance as of April 30, 2024 and April 30, 2023, respectively	$ (3,246)	$ (3,192)
Interest cost	(112)	(119)
Actuarial loss	16	(206)
Benefits paid	190	190
Foreign currency exchange rate changes	(183)	81
Pension benefit obligation balance as of April 30, 2025 and April 30, 2024, respectively	$ (3,335)	$ (3,246)

Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)(4)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-1

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- Definition

Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

+ References

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Amount of payment to participant of defined benefit plan which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
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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.

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No definition available.

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- Definition

Amount of foreign currency translation gain (loss) which (increases) decreases benefit obligation of defined benefit plan.

+ References

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- Definition

Amount of cost recognized for passage of time related to defined benefit plan.

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