Warrants (Schedule Of Assumptions Used In Calculating Fair Value Of Warrants) (Details) - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Class of Warrant or Right [Line Items]
Trading market prices	$ 5.16	$ 11.16
Estimated future volatility	102.00%	105.00%
Dividend
Estimated additional shares to be issued upon dilutive event	5.00%	5.00%
Minimum [Member]
Class of Warrant or Right [Line Items]
Estimated future risk-free rate	1.59%	2.35%
Equivalent volatility	84.00%	99.00%
Equivalent risk-free rate	1.86%	2.51%
Maximum [Member]
Class of Warrant or Right [Line Items]
Estimated future risk-free rate	1.76%	2.53%
Equivalent volatility	87.00%	104.00%
Equivalent risk-free rate	1.98%	2.55%