Income Taxes - Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income taxes
Income tax expense	$ 10	$ 34	$ 62	$ 75
Interest and penalties	0	0	0	0
Uncertain income tax positions recorded	0	0	0	0
Maximum
Income taxes
Income tax expense	$ 100	$ 100	$ 100	$ 100