Income Taxes - Components of Income tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
U.S. federal	$ 0	$ 0	$ (50)
U.S. State	368	298	395
Outside United States	7	13	78
Total Current	375	311	423
Deferred:
U.S. federal	71	(276)	(3,727)
U.S. State	(66)	(71)	(64)
Outside United States	58	(1)	0
Total Deferred	63	(348)	(3,791)
Total	$ 438	$ (37)	$ (3,368)