Summary of significant accounting policies - Trade Receivables, net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 391	$ 530
Provision	122	156
Write-offs	(27)	(127)
Recoveries of amounts previously written off	6	44
Balance, end of period	$ 492	$ 603