Quarterly report pursuant to Section 13 or 15(d)

Stock options and warrants (Schedule of Award Activity) (Details)

v3.2.0.727
Stock options and warrants (Schedule of Award Activity) (Details) - USD ($)
None in scaling factor is -9223372036854775296
3 Months Ended 6 Months Ended
Jun. 30, 2014
Jun. 30, 2015
Jun. 30, 2014
Shares Underlying Options      
Exercised (39,079)    
Weighted Average Exercise Price      
Exercised $ 2.09    
Stock Incentive Plan [Member]      
Shares Underlying Options      
Outstanding, beginning   1,854,258  
Granted   1,094,500  
Exercised      
Forfeited   (197,936) (36,040)
Outstanding, ending   2,750,822  
Exercisable   1,789,255  
Weighted Average Exercise Price      
Outstanding, beginning   $ 5.79  
Granted   $ 1.89  
Exercised      
Forfeited   $ 3.77  
Outstanding, ending   4.38  
Exercisable   $ 5.69  
Weighted Average Remaining Contractual Term      
Outstanding   8 years 3 months 18 days  
Outstanding and exercisable   7 years 9 months 18 days  
Aggregate Intrinsic Value      
Outstanding      
Outstanding and exercisable      
Nonqualified [Member]      
Shares Underlying Options      
Outstanding, beginning   3,455,935  
Granted      
Exercised      
Forfeited      
Outstanding, ending   3,455,935  
Weighted Average Exercise Price      
Outstanding, beginning   $ 1.93  
Granted      
Exercised      
Forfeited      
Outstanding, ending   $ 1.93  
Weighted Average Remaining Contractual Term      
Outstanding and exercisable   2 years 9 months 18 days  
Aggregate Intrinsic Value      
Outstanding