Summary of significant accounting policies - Strategic Investments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Accounting Policies [Abstract]
Balance of strategic investments	$ 7.7		$ 7.7		$ 5.4
Impairment loss on investment	0.9
Changes in carrying value of strategic investments	$ 0.0	$ 0.0	$ 0.0	$ 0.0