Marketable securities - Schedule of Unrealized Loss on Restricted Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Fair value
Less than 12 months	$ 5,457	$ 1,942
12 months or greater	26,468	29,826
Total	31,925	31,768
Unrealized losses
Less than 12 months	(25)	(27)
12 months or greater	(758)	(1,085)
Total	(783)	(1,112)
U.S. government agency securities and treasuries
Fair value
Less than 12 months	5,457	1,942
12 months or greater	26,468	29,826
Total	31,925	31,768
Unrealized losses
Less than 12 months	(25)	(27)
12 months or greater	(758)	(1,085)
Total	$ (783)	$ (1,112)