Annual report pursuant to Section 13 and 15(d)

Stock options, warrants and restricted common stock (Schedule of Award Activity) (Details)

v3.19.1
Stock options, warrants and restricted common stock (Schedule of Award Activity) (Details) - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Stock Incentive Plan [Member]    
Shares Underlying Options    
Outstanding, beginning 119,533 566,747
Granted 62,000 120,000
Exercised for cash (19,533) (50,800)
Forfeited (100,000) (516,414)
Outstanding, ending 62,000 119,533
Exercisable 57,836  
Weighted Average Exercise Price    
Outstanding, beginning $ 9.02 $ 20.46
Granted 15.71 9.00
Exercised for cash 4.02 2.94
Forfeited 10.00 22.16
Outstanding, ending 15.71 $ 9.02
Exercisable $ 15.51  
Weighted Average Remaining Contractual Term    
Outstanding 9 years 2 months 12 days 9 years 9 months 18 days
Exercisable 9 years 2 months 12 days  
Aggregate Intrinsic Value    
Outstanding $ 2,316,000
Exercisable  
Nonqualified [Member]    
Shares Underlying Options    
Outstanding, beginning 1,944,895 527,003
Granted 4,451,113
Exercised for cash (113,009) (620,000)
Exercised on a cashless basis   (2,244,147)
Forfeited (160,773) (169,074)
Outstanding, ending 1,671,113 1,944,895
Exercisable 1,671,113  
Weighted Average Exercise Price    
Outstanding, beginning $ 35.06 $ 13.36
Granted 17.03
Exercised for cash 3.50 3.00
Exercised on a cashless basis  
Forfeited 10.88 18.62
Outstanding, ending 39.47 $ 35.06
Exercisable $ 39.47  
Weighted Average Remaining Contractual Term    
Outstanding 2 years 2 years 8 months 12 days
Exercisable 2 years  
Aggregate Intrinsic Value    
Outstanding $ 6,135,000
Exercisable