Income taxes (Details 3) - USD ($)	Dec. 31, 2018	Dec. 31, 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 Assets, Net of Valuation Allowance	0	0
Deferred tax liabilities:
Property and equipment - U.S.	180,431	205,827
Intangible assets - U.S.	479,443	819,066
Deferred Tax Liabilities, Gross	659,874	1,024,893
Net deferred tax liability	$ 659,874	$ 1,024,893