Income taxes - Components of Income Taxes (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income taxes
Net loss	$ (37,127,303)	$ (53,478,812)	$ (28,059,807)
Foreign
Income taxes
Net loss	(13,229,828)	(27,215,385)	(25,268,373)
Domestic
Income taxes
Net loss	$ (23,897,475)	$ (26,263,427)	$ (2,791,434)