Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Stock Option Activity (Details)

v3.21.1
Stock-Based Compensation - Stock Option Activity (Details) - Tecogen - USD ($)
3 Months Ended 12 Months Ended
Mar. 31, 2021
Dec. 31, 2020
Dec. 31, 2018
Stock Options Outstanding [Roll Forward]      
Beginning (shares) 2,496,242    
Granted (shares) 8,000    
Exercised (shares) 0    
Canceled and forfeited (shares) (253,500)    
Ending (shares) 2,250,742 2,496,242  
Exercisable (shares) 591,908    
Vested and expected to vest (shares) 2,001,917    
Exercise Price Per Share [Abstract]      
Exercise Price Per Share, Outstanding, Minimum (per share) $ 0.71 $ 0.71  
Exercise Price Per Share, Outstanding, Maximum (dollars per share) 10.33 10.33  
Exercise price per share, Granted (dollars per share) 1.75    
Exercise Price, Canceled and Forfeited (dollars per share) 2.60    
Weighted Average Exercise Price [Roll Forward]      
Beginning (usd per share) 1.94    
Granted (usd per share) 1.75    
Exercised (usd per share)    
Canceled and forfeited (usd per share) 2.60    
Ending (usd per share) 1.87 $ 1.94  
Exercisable (usd per share) 4.03    
Vested and expected to vest (usd per share) $ 1.97    
Weighted Average Remaining Life 7 years 11 months 12 days   7 years 4 months 13 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]      
Outstanding, Aggregate Intrinsic Value $ 1,435,158 $ 731,744  
Exercisable, Aggregate Intrinsic Value 23,258    
Vested and expected to vest, Aggregate Intrinsic Value $ 1,223,373