Annual report pursuant to Section 13 and 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
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Shares not included in the computation of EPS 2,042,052 3,864,499
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 1,671,113 1,944,895
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 62,000 119,533
Unvested restricted stock awards [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Shares not included in the computation of EPS 95,939 342,070
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
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 1,458,001