Income taxes - Components of Income Tax Expense (Details) - USD ($)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Income components
United States	$ (5,378,499)	$ (5,300,760)
Outside United States	1,039,485	3,018,662
Loss before income taxes	(4,339,014)	(2,282,098)
Current
Federal	(944)	2,809
State	4,549	46,915
Foreign	328,783	899,207
Current, Total	332,388	948,931
Deferred
Federal	1,892,588	(941,331)
State	586,651	(435,241)
Foreign	(25,235)	(120,180)
Deferred, Total	2,454,004	(1,496,752)
Total provision for (benefit of) income taxes	$ 2,786,392	$ (547,821)