Retirement benefits (Details) - USD ($)	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Defined contribution plan
Retirement benefits
Defined contribution plan, cost	$ 918,496	$ 898,457	$ 771,616

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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+ Details