Annual report pursuant to Section 13 and 15(d)

Stockholders' equity - Stock-Based Compensation (Details)

v3.24.1
Stockholders' equity - Stock-Based Compensation (Details) - USD ($)
12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Jun. 09, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options granted, exercise price range, lower limit (usd per share) $ 0.88    
Options granted, exercise price range, upper limit (usd per share) $ 1.10 $ 10.33  
Historical forfeiture rate (percent) 15.00%    
Tecogen      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options granted 575,000 761,650  
Options granted, exercise price range, lower limit (usd per share)   $ 1.10  
Award vesting period   4 years  
Award expiration period   10 years  
Fair value of options issued   $ 321,910  
Weighted-average grant date fair value of options granted   $ 0.42  
Recognized stock-based compensation $ 250,394 $ 334,149  
Compensation cost related to unvested restricted stock awards and stock option awards not yet recognized $ 451,298 $ 500,059  
Compensation cost not yet recognized, weighted average period of recognition 2 years 9 months 7 days    
Tecogen | Director      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options granted 575,000 275,000  
Options granted, exercise price range, lower limit (usd per share) $ 0.88 $ 1.00  
Options granted, exercise price range, upper limit (usd per share) $ 1.10 $ 1.41  
Fair value of options issued $ 244,625 $ 145,600  
Weighted-average grant date fair value of options granted $ 0.43 $ 0.53  
Tecogen | Amended Plan | Stock Options      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Shares of common stock reserved for future issuance 3,838,750    
Number of shares remaining available for future issuance 243,818 146,393  
Tecogen | 2022 Stock Incentive Plan | Stock Options      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Shares of common stock reserved for future issuance 3,068,750   3,800,000