Income Taxes - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Tax Benefit (Provision) at Federal Rate	$ 436	$ (1,416)	$ (1,764)
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	0	(609)	0
State Tax Provision, Net of Federal Benefit	(417)	(376)	(462)
Change in Valuation Allowance	144	1,197	1,256
Other	(71)	11	(119)
Income Tax Provision	$ 92	$ (1,193)	$ (1,089)