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Share-based compensation (Details) - USD ($) $ in Millions	1 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024	Jun. 12, 2024	Jun. 11, 2020	Jun. 07, 2018
Share-based compensation
Aggregate common stock reserved for issuance	6,704,335	6,704,335
Share-based compensation arrangement by share based payment award percentage of fair market Person holding more then 10% voting stock		110.00%
2018 Stock Incentive Plan
Share-based compensation
Common stock reserved for issuance							4,000,000
2020 Stock Incentive Plan
Share-based compensation
Common stock reserved for issuance						3,000,000
2024 Stock Incentive Plan
Share-based compensation
Common stock reserved for issuance					3,000,000
Stock Option Plan
Share-based compensation
Stock option vesting period		2 years
Options granted under the Plans expire		10 years
Option to purchase granted		459,630		135,603
Stock Option Plan | Tranche one
Share-based compensation
Options vested		68,490		111,975
Stock Option Plan | Tranche two
Share-based compensation
Stock option vesting, percentage				50.00%
Stock Option Plan | Tranche three
Share-based compensation
Stock option vesting period				1 year
Stock option vesting, percentage				50.00%
Stock Option Plan | Minimum
Share-based compensation
Contractual term		3 years
Stock Option Plan | Maximum
Share-based compensation
Contractual term		10 years
Incentive Stock Options
Share-based compensation
Options granted under the Plans expire		5 years
Stock Appreciation Rights (SARs)
Share-based compensation
Stock option vesting period	2 years
Option to purchase granted	2,500
Selling, general and administrative expenses
Share-based compensation
Share-based compensation expense		$ 0.6	$ 0.8

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

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Aggregate number of common shares reserved for future issuance.

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

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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