Warrants - Warrants outstanding and exercisable (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Warrants
Warrants outstanding, beginning balance	2,401,818	6,473,964
Issuances	168,750	7,349,426
Exercises	(2,007,117)	(11,421,464)
Expirations and cancelations		(108)
Warrants outstanding, ending balance	563,451	2,401,818