Income taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]

The components of income before income taxes for the years ended December 31, 2018 and 2017 are as follows:

	Year Ended December 31,
	2018			2017
Foreign (not subject to income taxes)	$	15,100,642		$	10,041,971
Mexico		(3,115,656	)		(3,188,134	)
United States		(153,003	)		(2,010,241	)
		11,831,983			4,843,596
Less discontinued operations		(1,115,825	)		(1,041,234	)
	$	10,716,158		$	3,802,362

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

The Company's provision for income taxes for the years ended December 31, 2018 and 2017 consisted of a deferred tax benefit relating to U.S. operations made up of the following:

	Year Ended December 31,
	2018			2017
Current tax expense	$	207,728		$	1,371
Deferred tax benefit		(365,019	)		(890,348	)
	$	(157,291	)	$	(888,977	)

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

A reconciliation of the U.S. statutory federal tax rate to the effective benefit rate for the U.S. loss before income taxes for the years ended December 31, 2018 and 2017 is as follows:

	Year Ended December 31,
	2018			2017
U.S. statutory federal rate		21.00	%		34.00	%
State taxes, net of federal effect		4.22	%		2.00	%
Foreign tax rate differential		(38.26	)%		(82.91	)%
R&D tax credit		(2.27	)%		(2.49	)%
Permanent items		1.26	%		13.39	%
Tax Act adjustment		0.00	%		(11.25	)%
Valuation allowance for deferred tax assets		12.72	%		28.90	%
		(1.33	)%		(18.36	)%

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

The tax effects of significant items comprising the Company's net long-term deferred tax liability as of December 31, 2018 and 2017 were as follows:

	December 31,
	2018			2017
Deferred tax assets:
Operating loss carryforwards - Mexico	$	3,020,049		$	4,923,026
Land basis difference - Mexico		999,719			702,547
Start-up costs - Mexico		3,856,942			747,215
Valuation allowances		(7,876,710	)		(6,372,788	)
		-			-
Deferred tax liabilities:
Property and equipment - U.S.		180,431			205,827
Intangible assets - U.S.		479,443			819,066
		659,874			1,024,893
Net deferred tax liability	$	659,874		$	1,024,893