Segment information - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) segment	Dec. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	1
Non-US
Segment Reporting Information [Line Items]
Long-lived assets | $	$ 111.9	$ 98.6