Stock-based compensation - Stock options additional information (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
2018 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of options exercised	$ 2.1	$ 0.9	$ 3.8
2020 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of options exercised	$ 1.2	$ 0.5	$ 0.5
Weighted average grant date fair value	$ 6.74	$ 5.87	$ 6.93