Income taxes, Net Loss Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net Loss Before Income Taxes [Abstract]
Net loss before income taxes	$ (60,890)	$ (40,883)	$ (179,879)
United States [Member]
Net Loss Before Income Taxes [Abstract]
Net loss before income taxes	11,612	7,509	2,566
United Kingdom [Member]
Net Loss Before Income Taxes [Abstract]
Net loss before income taxes	(76,866)	(47,566)	(182,816)
Other Worldwide [Member]
Net Loss Before Income Taxes [Abstract]
Net loss before income taxes	$ 4,364	$ (826)	$ 371