Income Taxes - Components of Income Tax Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal	$ (107)	$ (140)	$ 0
State and local	(1,810)	(1,299)	(645)
NOL utilized	0	59	0
Deferred:
Federal	0	(44)	59
State and local	0	(15)	18
Benefit (provision) for income taxes	$ (1,917)	$ (1,439)	$ (568)