Shareholders' Equity, Stock Plans and Preferred Stock (Schedule of Weighted Average Grant Date Fair Value and Total Intrinsic Value of Exercises) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	[1]	Dec. 31, 2015	[1]
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Weighted average grant date fair value (in dollars per share)	$ 0.00	$ 0.00		$ 3.78
Total intrinsic value of exercises	$ 2	$ 3		$ 249

[1] The Company did not issue any options or other equity grants that would require application of the Black-Scholes-Merton equity grant valuation model during the years ended December 31, 2017 and 2016. All equity grants during this period were restricted common shares which are valued using an intrinsic valuation method based on market price.