Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Stock Option Activity (Details)

v3.8.0.1
Stock-Based Compensation - Stock Option Activity (Details) - Tecogen - USD ($)
 3 Months Ended 12 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Stock Options Outstanding [Roll Forward]    
Beginning (shares) 1,061,552  
Granted (shares) 37,000  
Exercised (shares) (40,204)  
Canceled and forfeited (shares) (35,609)  
Ending (shares) 1,022,739 1,061,552
Exercisable (shares) 811,864  
Vested and expected to vest (shares) 991,108  
Exercise Price Per Share [Abstract]    
Exercise Price Per Share, Outstanding, Minimum (per share) $ 0.79 $ 0.79
Exercise Price Per Share, Outstanding, Maximum (dollars per share) 18.15 18.15
Exercise Price Per Share, Exercised (dollars per share) 1.20  
Weighted Average Exercise Price [Roll Forward]    
Beginning (usd per share) 3.60  
Granted (usd per share) 2.43  
Exercised (usd per share) 1.20  
Canceled and forfeited (usd per share) 4.31  
Ending (usd per share) 3.62 $ 3.60
Exercisable (usd per share) 3.54  
Vested and expected to vest (usd per share) $ 3.61  
Weighted Average Remaining Life 5 years 4 months 28 days 4 years 11 months 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]    
Outstanding, Aggregate Intrinsic Value $ 312,550 $ 291,449
Exercisable, Aggregate Intrinsic Value 296,630  
Vested and expected to vest, Aggregate Intrinsic Value $ 312,550  
Minimum    
Exercise Price Per Share [Abstract]    
Exercise Price Per Share, Granted (dollars per share) $ 2.30  
Exercise Price, Assumed in Merger (dollars per share) 3.15  
Exercise Price, Canceled and Forfeited (dollars per share) 2.60  
Maximum    
Exercise Price Per Share [Abstract]    
Exercise Price Per Share, Granted (dollars per share) 2.70  
Exercise Price, Assumed in Merger (dollars per share) 30.33  
Exercise Price, Canceled and Forfeited (dollars per share) $ 6.74