Equity - Common stock warrants outstanding (Details) - $ / shares	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Class of Warrant or Right [Line Items]
Warrants outstanding (in shares)	10,819,742	11,308,314	392,155	392,155
Exercise price of warrants (in dollars per share)	$ 1.14	$ 1.09	$ 8.58	$ 8.58
July 2019 Series A warrants
Class of Warrant or Right [Line Items]
Warrants outstanding (in shares)	338,155
Exercise price of warrants (in dollars per share)	$ 8.75
April 2020 Series A warrants
Class of Warrant or Right [Line Items]
Warrants outstanding (in shares)	44,000
Exercise price of warrants (in dollars per share)	$ 7.50
April 2020 Series B warrants
Class of Warrant or Right [Line Items]
Warrants outstanding (in shares)	10,000
Exercise price of warrants (in dollars per share)	$ 7.50
June 2023 warrants
Class of Warrant or Right [Line Items]
Warrants outstanding (in shares)	1,427,587
Exercise price of warrants (in dollars per share)	$ 1.90
November 2023 Series A Warrants
Class of Warrant or Right [Line Items]
Warrants outstanding (in shares)	6,000,000
Exercise price of warrants (in dollars per share)	$ 0.70
November 2023 Series B Warrants
Class of Warrant or Right [Line Items]
Warrants outstanding (in shares)	3,000,000
Exercise price of warrants (in dollars per share)	$ 0.70