Quarterly report pursuant to Section 13 or 15(d)

Basis of presentation, summary of significant accounting policies (Schedule of Antidilutive Securities) (Details)

v3.20.2
Basis of presentation, summary of significant accounting policies (Schedule of Antidilutive Securities) (Details) - shares
6 Months Ended
Jun. 30, 2020
Jun. 30, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Shares not included in the computation of EPS 4,883,911 3,834,236
Warrants to purchase common stock [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Shares not included in the computation of EPS 3,554,257 3,574,257
Option to purchase common stock [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Shares not included in the computation of EPS 12,000 12,000
Escrow shares [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Shares not included in the computation of EPS 200,000
Unvested restricted stock awards [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Shares not included in the computation of EPS 1,313,455 42,980
Convertible Series B Preferred Shares [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Shares not included in the computation of EPS 4,199 4,999