Revenue from contracts with customers (Schedule of Revenues by Geography) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 4,214,441	$ 3,498,614
Domestic [Member]
Disaggregation of Revenue [Line Items]
Total revenue	1,917,367	3,322,615
International [Member]
Disaggregation of Revenue [Line Items]
Total revenue	$ 2,297,074	$ 175,999