Quarterly report pursuant to Section 13 or 15(d)

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

v3.20.1
Basis of presentation, summary of significant accounting policies (Schedule of Antidilutive Securities) (Details) - shares
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Shares not included in the computation of EPS 5,015,480 5,701,299
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 3,579,257
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 62,000
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 1,445,024 33,542
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 13,000
Convertible notes [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Shares not included in the computation of EPS 1,813,500