Stock-based compensation - Summary of significant valuation assumptions (Details)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
2020 Stock Option and Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, minimum	3.97%	3.56%
Risk-free interest rate, maximum	4.43%	4.46%
Expected volatility, minimum	96.87%	102.82%
Expected volatility, maximum	102.94%	104.41%
Expected dividend yield	0.00%	0.00%
2020 Stock Option and Incentive Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected option life (years)	5 years 6 months	5 years 6 months
2020 Stock Option and Incentive Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected option life (years)	6 years 29 days	6 years 1 month 9 days
Inducement Grants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, minimum		3.63%
Risk-free interest rate, maximum		4.64%
Expected volatility, minimum		103.11%
Expected volatility, maximum		103.85%
Expected dividend yield		0.00%
Inducement Grants | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected option life (years)		6 years 29 days
Inducement Grants | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected option life (years)		6 years 1 month 9 days