Convertible debt - Schedule of KSP Convertible Notes Valuation Assumptions (Details) - KSP Convertible Notes	Dec. 31, 2023	Dec. 31, 2022	Oct. 31, 2022	Oct. 31, 2021	Sep. 29, 2021
Risk free interest rate
Debt Conversion [Line Items]
Embedded derivative liability, measurement input	0.041	0.042	0.044	0.012	0.011
Expected life of options
Debt Conversion [Line Items]
Embedded derivative liability, measurement input	2.7	3.8	3.9	4.9	5.0
Expected dividend yield
Debt Conversion [Line Items]
Embedded derivative liability, measurement input	0.000	0.000	0.000	0.000	0.000
Expected stock price volatility
Debt Conversion [Line Items]
Embedded derivative liability, measurement input	0.65	0.63	0.63	0.62	0.66
Share Price
Debt Conversion [Line Items]
Embedded derivative liability, measurement input	0.58	4.76	5.96	12.94	12.56