Income Taxes, Components of Benefit (Provision) for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current [Abstract]
Federal	$ 0	$ 0	$ 10
State	(3)	(133)	(18)
Foreign	0	0	0
Current income taxes	(3)	(133)	(8)
Deferred [Abstract]
Federal	0	0	0
State	0	0	0
Total income tax provision	$ (3)	$ (133)	$ (8)