Stockholders' Equity And Stock-Based Compensation Expense (Common Stock Outstanding and Stockholders' Equity) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Common Stock, Beginning balance	21,841,810	17,219,300
Common Stock, Proceeds from exercise of common stock warrants	2,888,092
Common Stock, Issuance costs from sale 2018 sale of common stock and warrants
Common Stock, Net loss
Common Stock, Ending balance	24,729,902	17,219,300
Stockholders' equity, Beginning balance	$ 22,099	$ 19,628
Stockholders' equity, Non-cash stock-based compensation for:	270	344
Stockholders' equity, Proceeds from exercise of common stock warrants	3,613
Stockholders' Equity, Issuance of common stock and warrants, net of issuance costs		(60)
Net loss	(1,150)	(1,359)
Stockholders' equity, Ending balance	$ 24,832	$ 18,553
Stock Options [Member]
Common Stock, Non-cash stock-based compensation for:
Stockholders' equity, Non-cash stock-based compensation for:	$ 261	$ 342
Non-Employee Stock Options [Member]
Common Stock, Non-cash stock-based compensation for:
Stockholders' equity, Non-cash stock-based compensation for:	$ 9	$ 2