Other income, net - Schedule of Other Income Net (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Other Income And Expenses [Abstract]
Interest income	$ 434	$ 450
Foreign exchange gains	15	2
Other expenses	(20)	(1)
Total Other income (expenses)	$ 429	$ 451