Computation of Net Loss Per Share of Common Stock (Components Of Net Income (Loss) Per Basic And Diluted Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net loss	$ (4,530)	$ (3,562)
Loss per share, basic and diluted	$ (0.48)	$ (0.39)