Accounting policies - Disaggregated revenue (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Total Revenue	$ 68,793,651	$ 65,719,857
Retail revenue [Member]
Total Revenue	26,456,022	25,621,048
Bulk revenue [Member]
Total Revenue	26,986,108	31,031,287
Services revenue [Member]
Total Revenue	1,759,446	1,811,372
Manufacturing revenue [Member]
Total Revenue	$ 13,592,075	$ 7,256,150