Stock-based compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		6 Months Ended
	Mar. 07, 2024	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted (in shares)				2,172,150
Stock options granted, weighted average exercise price (in dollars per share)				$ 2.92
Stock options granted, weighted average grant date fair value (in dollars per share)				$ 2.33
2020 Stock Option and Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted, weighted average exercise price (in dollars per share)	$ 22.00
New exercise price per share, tranche two (in dollars per share)	11.88
New exercise price per share, tranche one (in dollars per share)	$ 19.00
Share-based payment arrangement, plan modification, incremental cost		$ 0.1	$ 0.4	$ 0.3	$ 0.5
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation costs		$ 21.4		$ 21.4
Expected to be recognized over a weighted average period				2 years
Performance-based RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Units vested (in shares)				0
Shares forfeited (in shares)				98,000
Share-based compensation, number of common stock issuable per RSU vested (in shares)		1		1
Restricted stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation costs		$ 11.5		$ 11.5
Expected to be recognized over a weighted average period				3 years 2 months 12 days
Units vested (in shares)				369,967
Granted (in shares)				1,954,500
Number of shares retained to cover statutory minimum withholding taxes (in shares)				48,625
Shares outstanding (in shares)		2,957,988		2,957,988