Quarterly report [Sections 13 or 15(d)]

Stock-Based Compensation - Stock Option Activity (Details)

v3.26.1
Stock-Based Compensation - Stock Option Activity (Details) - USD ($)
3 Months Ended 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Stock Options Outstanding [Roll Forward]      
Exercised (shares) (58,750) (35,000)  
Exercise Price Per Share [Abstract]      
Exercise Price Per Share, Outstanding, Minimum (in dollars per share) $ 0.71    
Exercise Price Per Share, Outstanding, Maximum (in dollars per share) 8.61    
Exercise price per share, granted (in dollars per share) 2.36    
Exercise price per share, exercised, lower range limit (in dollars per share) 0.88    
Exercise price per share, exercised, upper range limit (in dollars per share) 1.20    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]      
Share Based Compensation Shares Authorized Under Stock Option Plans, Cancelled and Forfeited, Exercise Price Range, Lower Range Limit 0.71    
Share Based Compensation Shares Authorized Under Stock Option Plans, Cancelled and Forfeited, Exercise Price Range, Upper Range Limit $ 3.93    
Tecogen      
Stock Options Outstanding [Roll Forward]      
Beginning (shares) 2,347,044    
Granted (shares) 50,000    
Exercised (shares) (58,750)    
Canceled and forfeited (shares) (65,500)    
Ending (shares) 2,272,794   2,347,044
Exercisable (shares) 1,400,458    
Vested and expected to vest (shares) 2,141,944    
Exercise Price Per Share [Abstract]      
Exercise Price Per Share, Outstanding, Minimum (in dollars per share)     $ 0.71
Exercise Price Per Share, Outstanding, Maximum (in dollars per share)     8.61
Weighted Average Exercise Price [Roll Forward]      
Beginning (usd per share) $ 1.90    
Granted (usd per share) 2.36    
Exercised (usd per share) 0.93    
Canceled and forfeited (usd per share) 0.95    
Ending (usd per share) 1.97   $ 1.90
Exercisable (usd per share) 1.26    
Vested and expected to vest (usd per share) $ 1.90    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]      
Outstanding, Aggregate Intrinsic Value $ 2,933,445   $ 7,961,973
Exercised, Aggregate Intrinsic Value 95,900    
Exercisable, Aggregate Intrinsic Value 1,980,445    
Vested and expected to vest, Aggregate Intrinsic Value $ 2,790,495    
Tecogen | Stock Options      
Weighted Average Exercise Price [Roll Forward]      
Weighted Average Remaining Life 6 years 1 month 6 days   6 years 3 months 14 days