Basis of presentation - Schedule of Other Income (Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interest income	$ 414	$ 1,930	$ 3,724	$ 6,187
Interest expense	(973)	0	(1,115)	0
Loss from equity-method investments	(627)	(239)	(2,559)	(406)
Net foreign exchange loss	(676)	(378)	(2,019)	(1,623)
Other	(139)	936	(615)	1,221
Other (expense) income	$ (2,001)	$ 2,249	$ (2,584)	$ 5,379