Fair value measurements - Narrative (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Reclassification of assets, Level 2 to Level 3	$ 0	$ 0
Reclassification of liabilities, Level 2 to Level 3	0	0
Reclassification of assets, Level 3 to Level 2	0	0
Reclassification of liabilities, Level 3 to Level 2	$ 0	$ 0