Warrants - Warrants outstanding and exercisable (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Warrants
Warrants outstanding, beginning balance	19,421,892	34,682
Issuances	22,048,278	20,637,761
Exercises	(34,264,393)	(1,250,000)
Expirations and cancelations	(323)	(551)
Warrants outstanding, ending balance	7,205,454	19,421,892