Accounting policies - Cash and cash equivalents (Details) - USD ($)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Net foreign currency gains	$ 39,259	$ 74,993	$ 84,678
Cash and cash equivalents	61,779,089	35,038,857
Money Market Funds, at Carrying Value	18,100,000	10,600,000
Deposits	44,000,000
Cash held in foreign bank accounts	58,700,000
Deposits held in foreign bank	12,000,000	7,700,000
Certificate of deposit
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	$ 17,000,000	$ 5,200,000