Annual report pursuant to Section 13 and 15(d)

Stockholders' equity - Stock-Based Compensation (Details)

v3.3.1.900
Stockholders' equity - Stock-Based Compensation (Details) - USD ($)
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options granted, exercise price range, lower limit (usd per share) $ 3.39  
Options granted, exercise price range, upper limit (usd per share) $ 4.05  
Warrants granted 250,000  
Tecogen    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options granted 165,000 318,325
Options granted, exercise price range, lower limit (usd per share) $ 3.39 $ 4.50
Options granted, exercise price range, upper limit (usd per share) $ 4.05 $ 5.39
Fair value of options issued $ 250,462 $ 577,029
Weighted-average grant date fair value of options granted $ 1.52 $ 1.89
Recognized stock-based compensation $ 189,511 $ 117,138
Compensation cost related to unvested restricted stock awards and stock option awards not yet recognized $ 592,494 $ 156,179
Compensation cost not yet recognized, weighted average period of recognition 2 years 11 months 15 days  
Tecogen | Stock Options    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Award vesting period 4 years 4 years
Award expiration period 10 years 10 years
Tecogen | Restricted stock    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Unvested restricted stock outstanding 163,350 163,350
Tecogen | Restricted stock | Maximum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Award vesting period 2 years  
Vesting percentage 25.00%  
Tecogen | Performance Shares    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options granted   100,000
Award vesting period   1 year
Tecogen | Amended Plan | Stock Options    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Shares of common stock reserved for future issuance 3,838,750  
Number of shares remaining available for future issuance 1,614,533 1,748,783
Ilois    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options granted 0  
Recognized stock-based compensation $ 9,989 $ 9,798
Compensation cost related to unvested restricted stock awards and stock option awards not yet recognized $ 4,489 $ 9,004
Compensation cost not yet recognized, weighted average period of recognition 4 months 11 days  
Ilois | Restricted stock    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Unvested restricted stock outstanding 160,000 310,000
Ilois | Restricted stock | Minimum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Award vesting period 90 days  
Vesting percentage 100.00%  
Ilois | Restricted stock | Maximum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Award vesting period 1 year  
Vesting percentage 100.00%  
Ilois | 2009 Plan    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Maximum number of shares allowable for issuance 2,000,000