Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Stock Option Activity (Details)

v3.19.2
Stock-Based Compensation - Stock Option Activity (Details) - Tecogen - USD ($)
 6 Months Ended 12 Months Ended
Jun. 30, 2019
Dec. 31, 2017
Dec. 31, 2018
Stock Options Outstanding [Roll Forward]      
Beginning (shares) 1,292,589    
Granted (shares) 88,500    
Exercised (shares) (16,060)    
Canceled and forfeited (shares) (700)    
Ending (shares) 1,364,329    
Exercisable (shares) 910,329    
Vested and expected to vest (shares) 1,296,229    
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) 10.33 $ 10.33  
Exercise Price, Canceled and Forfeited (dollars per share) 4.50    
Weighted Average Exercise Price [Roll Forward]      
Beginning (usd per share) 3.52    
Granted (usd per share) 3.70    
Exercised (usd per share) 1.29    
Canceled and forfeited (usd per share) 4.50    
Ending (usd per share) 3.56    
Exercisable (usd per share) 3.50    
Vested and expected to vest (usd per share) $ 3.55    
Weighted Average Remaining Life 5 years 9 months 10 days 5 years 11 months 6 days  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]      
Outstanding, Aggregate Intrinsic Value $ 722,514   $ 671,331
Exercisable, Aggregate Intrinsic Value 655,677    
Vested and expected to vest, Aggregate Intrinsic Value $ 712,488    
Minimum      
Exercise Price Per Share [Abstract]      
Exercise Price Per Share, Granted (dollars per share) $ 3.62    
Exercise Price Per Share, Exercised (dollars per share) 1.20    
Maximum      
Exercise Price Per Share [Abstract]      
Exercise Price Per Share, Granted (dollars per share) 3.80    
Exercise Price Per Share, Exercised (dollars per share) $ 2.60