Stock-based compensation - Schedule of Employee stock-based compensation recognized (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	$ 9,113	$ 5,126	$ 21,459	$ 13,584
Unrecognized stock-based compensation expense	30,300		30,300
Cost of revenue
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	173	66	433	740
Engineering, research, and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	799	621	1,970	1,678
Sales and marketing
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	963	808	2,207	2,545
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	$ 7,178	$ 3,631	$ 16,849	$ 8,621