Stock-based compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended	9 Months Ended
	Mar. 07, 2024	Sep. 30, 2024	Sep. 30, 2024
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted (in shares)			3,382,967
Stock options granted, weighted average exercise price (in dollars per share)			$ 6.86
Stock options granted, weighted average grant date fair value (in dollars per share)			$ 5.62
Stock repurchased during period (shares)			6,634
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 one (in dollars per share)	19.00
New exercise price per share, tranche two (in dollars per share)	$ 11.88
Share-based payment arrangement, plan modification, incremental cost		$ 0.4	$ 0.9
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation costs		41.9	$ 41.9
Expected to be recognized over a weighted average period			2 years 3 months 18 days
Performance-based RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation costs		$ 2.4	$ 2.4
Units vested (in shares)			21,000
Share-based compensation, number of common stock issuable per RSU vested (in shares)		1	1
Time-based RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation costs		$ 8.9	$ 8.9
Expected to be recognized over a weighted average period			3 years 1 month 6 days
Units vested (in shares)			161,862
Granted (in shares)			1,013,350
Number of shares retained to cover statutory minimum withholding taxes (in shares)			23,349