Cost of revenues and general and administrative expenses - General and administrative expenses (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cost of revenues and general and administrative expenses [Line Items]
General and Administrative Expense	$ 18,350,359	$ 18,434,898
Employee costs [Member]
Cost of revenues and general and administrative expenses [Line Items]
General and Administrative Expense	9,562,125	10,086,588
Insurance [Member]
Cost of revenues and general and administrative expenses [Line Items]
General and Administrative Expense	1,813,026	1,436,957
Professional fees [Member]
Cost of revenues and general and administrative expenses [Line Items]
General and Administrative Expense	1,506,423	1,488,948
Directors' fees and expenses [Member]
Cost of revenues and general and administrative expenses [Line Items]
General and Administrative Expense	851,775	865,555
Depreciation [Member]
Cost of revenues and general and administrative expenses [Line Items]
General and Administrative Expense	140,140	133,477
Amortization of intangibles [Member]
Cost of revenues and general and administrative expenses [Line Items]
General and Administrative Expense	746,667	891,667
Other [Member].
Cost of revenues and general and administrative expenses [Line Items]
General and Administrative Expense	$ 3,730,203	$ 3,531,706