Annual report pursuant to Section 13 and 15(d)

Stock options and warrants (Stock incentive plan options) (Narrative) (Details)

v3.7.0.1
Stock options and warrants (Stock incentive plan options) (Narrative) (Details) - USD ($)
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number of shares reserved under the Plan 895,000 709,141
Minimum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expiration period 3 years  
Maximum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expiration period 5 years  
Stock Incentive Plan [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Incentive stock options exercised to purchase common shares  
Options granted 259,666 136,813
Options granted, exercise price $ 2.90 $ 15.12
Expiration period 10 years  
Options vested 191,644  
Vesting rate 80.00%  
Options forfeited 25,479 36,099
Options expired   7,894
Options forfeited, unvested 3,620 28,205
Options forfeited, exercise price $ 36.88  
Options forfeited, unvested, exercise price $ 15.13 $ 16.48
Fair value of options vested $ 646,000 $ 1,344,000
Expected to vest 78,000  
Unrecognized compensation cost $ 133,000  
Unrecognized compensation cost, period for recognition 1 year  
Stock Incentive Plan [Member] | Independent Directors [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options granted 109,666 43,000
Options granted, exercise price $ 2.92 $ 15.12
Expiration period 10 years 10 years
Vesting period 1 year 1 year
Vesting rate   25.00%
Stock Incentive Plan [Member] | Officer [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options granted 128,000  
Options granted, exercise price $ 2.89  
Expiration period 10 years  
Vesting period 1 year  
Stock Incentive Plan [Member] | Officers and Employees [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options granted 2,000 93,813
Options granted, exercise price $ 2.89 $ 15.12
Expiration period 10 years 10 years
Vesting period 1 year 2 years
Vesting rate   50.00%
Stock Incentive Plan [Member] | Officers Employees and Consultant [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options granted 20,000  
Options granted, exercise price $ 2.89  
Expiration period 10 years  
Vesting period 1 year  
Stock Incentive Plan [Member] | Vested Options [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options forfeited 21,859  
Options forfeited, exercise price $ 40.49  
Stock Incentive Plan [Member] | Unvested Options [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options forfeited 3,620  
Options forfeited, exercise price $ 72.32