Earnings (loss) per common share (Details) (USD $)
3 Months Ended 9 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2012
Sep. 30, 2011
Numerator [Abstract]        
Net income (loss) - basic and diluted $ (367,077) $ (5,244,745) $ (11,503,729) $ (4,905,194)
Preferred stock dividend and accretion 221,142 222,281 627,031 660,508
Net loss available to common shareholders $ (588,219) $ (5,467,026) $ (12,130,760) $ (5,565,702)
Denominator [Abstract]        
Weighted average shares outstanding - basic (in shares) 4,250,990 4,243,378 4,250,990 4,242,905
Dilutive effect of common stock options and restricted stock awards (in shares) 0 0 0 0
Weighted average shares outstanding - diluted (in shares) 4,250,990 4,243,378 4,250,990 4,242,905
Earnings (loss) per share - basic and diluted [Abstract]        
Earnings (loss) per share - basic (in dollars per share) $ (0.14) $ (1.29) $ (2.85) $ (1.31)
Effect of dilutive common stock options (in dollars per share) $ 0 $ 0 $ 0 $ 0
Earnings (loss) per share - diluted (in dollars per share) $ (0.14) $ (1.29) $ (2.85) $ (1.31)
Stock Options [Member]
       
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) 266,530   266,530  
Warrants [Member]
       
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)     499,029 499,029