Income Taxes - Components of provision for income taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Provision for income tax benefit (expense)
Income tax benefit (expense)	$ 5	$ 220	$ (519)	$ (7)
Provision for income taxes on undistributed earnings of foreign subsidiaries	$ 0		$ 0