General form of registration statement for all companies including face-amount certificate companies

Stock-based compensation - Stock Option Activity (Details)

v2.4.0.8
Stock-based compensation - Stock Option Activity (Details) (USD $)
 9 Months Ended 12 Months Ended
Sep. 30, 2013
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Tecogen
          
Stock Options Outstanding [Roll Forward]          
Beginning (in shares) 1,096,500 1,095,250 620,000 595,000  
Granted (in shares) 37,500 17,500 511,500 25,000  
Exercised (in shares) 0 0 0    
Canceled and forfeited (in shares) 0 (15,938) 0    
Repurchased (in shares)     (12,500)    
Expired (in shares) 0 (313) (23,750)    
Ending (in shares) 1,134,000 1,096,500 1,095,250 620,000 595,000
Exercisable (in shares) 815,438 662,563 418,438 307,500  
Vested and expected to vest (in shares) 1,134,000 1,096,500 1,025,250 620,000  
Weighted Average Exercise Price [Roll Forward]          
Beginning (in dollars per share) $ 1.96 $ 1.92 $ 1.20 $ 1.28  
Granted (in dollars per share) $ 3.20 $ 3.20 $ 2.60 $ 2.60  
Exercised (in dollars per share) $ 0 $ 0 $ 0    
Canceled and forfeited (in dollars per share) $ 0 $ 1.28 $ 0    
Repurchased (in dollars per share)     $ 1.00    
Expired (in dollars per share) $ 0 $ 2.60 $ 1.48    
Ending (in dollars per share) $ 2.00 $ 1.96 $ 1.92 $ 1.20 $ 1.28
Exercisable (in dollars per share) $ 1.73 $ 1.56 $ 1.24 $ 1.12  
Vested and expected to vest (in dollars per share) $ 2.00 $ 1.96 $ 1.92 $ 1.20  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]          
Outstanding, Weighted Average Remaining Life 3 years 11 months 8 days 4 years 7 months 28 days 5 years 6 months 11 days 3 years 3 months 18 days 4 years 3 months 7 days
Outstanding, Aggregate Intrinsic Value $ 1,356,400 $ 1,356,400 $ 1,387,150 $ 793,500 $ 793,500
Exercisable, Aggregate Intrinsic Value 1,201,075 1,096,225 815,125 451,000  
Vested and expected to vest, Aggregate Intrinsic Value 1,356,400 1,356,400 1,387,150 793,500  
Exercise Price Per Share [Abstract]          
Outstanding, Exercise Price Lower Range Limit (in dollars per share)   $ 0.12 $ 0.12 $ 0.12  
Outstanding, Exercise Price Upper Range Limit (in dollars per share)   $ 3.2 $ 2.8   $ 2
Granted, Exercise Price (in dollars per share) $ 3.20 $ 3.20   $ 2.60  
Granted, Exercise Price Lower Range Limit (in dollars per share)     $ 2.6    
Granted, Exercise Price Upper Range Limit (in dollars per share)     $ 2.8    
Exercised, Exercise Price (in dollars per share) $ 0 $ 0 $ 0    
Canceled and Forfeited, Exercise Price (in dollars per share) $ 0   $ 0    
Canceled and Forfeited, Exercise Price Lower Range Limit (in dollars per share)   $ 1.2      
Canceled and Forfeited, Exercise Price Upper Range Limit (in dollars per share)   $ 2.6      
Repurchased, Exercise Price (in dollars per share)     $ 1.00    
Expired, Exercise Price (in dollars per share) $ 0 $ 2.60      
Expired, Exercise Price Per Share, Lower Range Limit (in dollars per share)     $ 1.2    
Expired, Exercise Price Per Share, Upper Range Limit (in dollars per share)     $ 2.6    
Tecogen | Minimum [Member]
          
Exercise Price Per Share [Abstract]          
Outstanding, Exercise Price (in dollars per share) $ 0.12        
Tecogen | Maximum [Member]
          
Exercise Price Per Share [Abstract]          
Outstanding, Exercise Price (in dollars per share) $ 3.20        
Ilois
          
Stock Options Outstanding [Roll Forward]          
Beginning (in shares) 575,000 525,000 300,000 300,000  
Granted (in shares) 0 50,000 225,000 0  
Exercised (in shares) 0 0 0 0  
Canceled and forfeited (in shares) 0 0 0 0  
Expired (in shares) 0 0 0 0  
Ending (in shares) 575,000 575,000 525,000 300,000 300,000
Exercisable (in shares) 62,500 0 0 0  
Vested and expected to vest (in shares) 575,000 575,000 525,000 300,000  
Weighted Average Exercise Price [Roll Forward]          
Beginning (in dollars per share) $ 0.29 $ 0.27 $ 0.10 $ 0.10  
Granted (in dollars per share) $ 0 $ 0.50 $ 0.50 $ 0  
Exercised (in dollars per share) $ 0 $ 0 $ 0 $ 0  
Canceled and forfeited (in dollars per share) $ 0 $ 0 $ 0 $ 0  
Expired (in dollars per share) $ 0 $ 0 $ 0 $ 0  
Ending (in dollars per share) $ 0.29 $ 0.29 $ 0.27 $ 0.10 $ 0.10
Exercisable (in dollars per share) $ 0.50 $ 0.50 $ 0 $ 0  
Vested and expected to vest (in dollars per share) $ 0.29 $ 0.29 $ 0.27 $ 0.10  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]          
Outstanding, Weighted Average Remaining Life 6 years 11 months 26 days 7 years 5 months 8 days 8 years 2 months 23 days 8 years 4 months 2 days 9 years 4 months 2 days
Outstanding, Aggregate Intrinsic Value 120,000 120,000 120,000 120,000 120,000
Exercisable, Aggregate Intrinsic Value 0 0 0 0  
Vested and expected to vest, Aggregate Intrinsic Value $ 120,000 $ 120,000 $ 120,000 $ 120,000  
Exercise Price Per Share [Abstract]          
Outstanding, Exercise Price (in dollars per share)     $ 0.10   $ 0.10
Outstanding, Exercise Price Lower Range Limit (in dollars per share)   $ 0.1 $ 0.1    
Outstanding, Exercise Price Upper Range Limit (in dollars per share)   $ 0.5 $ 0.5    
Granted, Exercise Price (in dollars per share) $ 0 $ 0.50 $ 0.50 $ 0  
Exercised, Exercise Price (in dollars per share) $ 0 $ 0 $ 0 $ 0  
Canceled and Forfeited, Exercise Price (in dollars per share) $ 0 $ 0 $ 0 $ 0  
Expired, Exercise Price (in dollars per share) $ 0 $ 0 $ 0 $ 0  
Ilois | Minimum [Member]
          
Exercise Price Per Share [Abstract]          
Outstanding, Exercise Price (in dollars per share) $ 0.10        
Ilois | Maximum [Member]
          
Exercise Price Per Share [Abstract]          
Outstanding, Exercise Price (in dollars per share) $ 0.50