Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.1
Basis of presentation, summary of significant accounting policies (Schedule of Antidilutive Securities) (Details) - shares
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Shares not included in the computation of EPS 5,701,299 3,791,062
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 3,579,257 1,831,886
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 62,000 150,000
Unvested restricted stock awards [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Shares not included in the computation of EPS 33,542 681,176
Escrow shares of common stock [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Shares not included in the computation of EPS 200,000 200,000
Convertible Preferred Stock Series B [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Shares not included in the computation of EPS 13,000 928,000
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