Income taxes - Effective Income Tax Rate Reconciliation (Details) - USD ($)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Amount
Income tax expense at Federal statutory tax rate	$ (911,194)	$ (479,240)
Increase (decrease) in tax rate resulting from:	311,429	(306,778)
Nontaxable or nondeductible items	25,721	185,639
Valuation allowance	3,419,636	0
Other adjustments	(136,228)	(92,995)
Total provision for (benefit of) income taxes	$ 2,786,392	$ (547,821)
Percent
Income tax expense at Federal statutory tax rate	21.00%	21.00%
State and local income taxes, net of federal benefit(1)	(7.20%)	13.40%
Nontaxable or nondeductible items	(0.60%)	(8.10%)
Valuation allowance	(78.80%)	0.00%
Other adjustments	3.20%	4.10%
Income tax expense	(64.20%)	24.00%
Hong Kong
Amount
State and local income taxes, net of federal benefit(1)	$ (54,845)	$ (165,121)
Percent
Foreign tax effects (statutory rate differential)	1.30%	7.30%
Canada
Amount
State and local income taxes, net of federal benefit(1)	$ 158,369	$ 150,688
Percent
Foreign tax effects (statutory rate differential)	(3.70%)	(6.60%)
Cayman Islands
Amount
State and local income taxes, net of federal benefit(1)	$ 184,621	$ 134,299
Percent
Foreign tax effects (statutory rate differential)	(4.30%)	(5.90%)
Other
Amount
State and local income taxes, net of federal benefit(1)	$ (87,185)	$ 34,313
Percent
Foreign tax effects (statutory rate differential)	2.00%	(1.60%)
CAMBODIA
Amount
State and local income taxes, net of federal benefit(1)	$ (123,932)	$ (8,626)
Percent
Foreign tax effects (statutory rate differential)	2.90%	0.40%