Stock-based compensation - Stock compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock compensation expense	$ 4,610	$ 449
Cost of revenue [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock compensation expense	309	66
Research and development [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock compensation expense	188	14
Selling and marketing [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock compensation expense	530	9
General and administrative [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock compensation expense	$ 3,583	$ 360