Revenue recognition - Deferred Contracts Costs Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Deferred contract costs [Roll Forward]
Balance at Beginning of Period	$ 25,837	$ 14,380	$ 6,733
Additions	36,509	18,943	10,685
Amortization Expense	(17,801)	(7,486)	(3,038)
Balance at End of Period	$ 44,545	$ 25,837	$ 14,380