Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Stock Option Activity (Details)

v3.22.1
Stock-Based Compensation - Stock Option Activity (Details) - Tecogen - USD ($)
 3 Months Ended 12 Months Ended
Mar. 31, 2022
Dec. 31, 2021
Dec. 31, 2019
Stock Options Outstanding [Roll Forward]      
Beginning (shares) 2,386,842    
Granted (shares) 726,650    
Exercised (shares) 0    
Canceled and forfeited (shares) (4,525)    
Ending (shares) 3,108,967 2,386,842  
Exercisable (shares) 731,592    
Vested and expected to vest (shares) 2,752,361    
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  
Weighted Average Exercise Price [Roll Forward]      
Beginning (usd per share) 1.81    
Granted (usd per share) 1.10    
Canceled and forfeited (usd per share) 1.63    
Ending (usd per share) 1.64 $ 1.81  
Exercisable (usd per share) 3.52    
Vested and expected to vest (usd per share) $ 1.72    
Weighted Average Remaining Life 7 years 10 months 24 days   7 years 6 months 21 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]      
Outstanding, Aggregate Intrinsic Value $ 1,751,592 $ 731,744  
Exercisable, Aggregate Intrinsic Value 139,485    
Vested and expected to vest, Aggregate Intrinsic Value $ 1,509,777    
Minimum      
Exercise Price Per Share [Abstract]      
Exercise price per share, Granted (dollars per share) $ 1.10    
Exercise Price, Canceled and Forfeited (dollars per share) 1.10    
Maximum      
Exercise Price Per Share [Abstract]      
Exercise price per share, Granted (dollars per share) 1.13    
Exercise Price, Canceled and Forfeited (dollars per share) $ 4.50