Income taxes - Components of income before income taxes (Details) - USD ($)	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Income taxes
Foreign (not subject to income taxes)	$ 6,958,583	$ 5,780,692
Mexico	(987,279)	(1,767,915)
United States	1,394,642	(2,952,265)
Income before income taxes	7,365,946	1,060,512
Less discontinued operations	2,371,049	2,574,079
Income before income taxes	$ 9,736,995	$ 3,634,591

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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+ Details