Income Taxes - Components of benefit for income taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current income tax provision (benefit)
Federal									$ (24)	$ 49	$ (25)
State									(27)	61	7
Total current income tax provision (benefit)									(51)	110	(18)
Deferred income tax (benefit) provision
Federal									(435)	(295)	(167)
State									(238)	(69)	(211)
Total deferred income tax (benefit)									(673)	(364)	(378)
Total benefit from income taxes	$ (55)	$ (465)	$ (97)	$ (107)	$ (138)	$ (331)	$ 135	$ 80	$ (724)	$ (254)	$ (396)