Registration of securities issued in business combination transactions

Warrants (Schedule Of Assumptions Used In Calculating Fair Value Of Warrants) (Details)

v3.20.2
Warrants (Schedule Of Assumptions Used In Calculating Fair Value Of Warrants) (Details) - $ / shares
 6 Months Ended 12 Months Ended
Jun. 30, 2020
Dec. 31, 2019
Dec. 31, 2018
Class of Warrant or Right [Line Items]      
Trading market prices $ 2.84 $ 1.91 $ 11.16
Estimated future volatility 134.00% 102.00% 105.00%
Dividend
Equivalent risk-free rate 0.16%    
Fundamental transaction likelihood 90.00% 50.00% 5.00%
Fundamental transaction timing 2020-09 2020-04  
Fundamental transaction timing     End of warrant term
Minimum [Member]      
Class of Warrant or Right [Line Items]      
Estimated future risk-free rate 0.17% 1.57% 2.35%
Equivalent volatility 92.00% 85.00% 99.00%
Equivalent risk-free rate   1.57% 2.51%
Maximum [Member]      
Class of Warrant or Right [Line Items]      
Estimated future risk-free rate 0.21% 1.72% 2.53%
Equivalent volatility 103.00% 94.00% 104.00%
Equivalent risk-free rate   1.59% 2.55%