Annual report pursuant to Section 13 and 15(d)

Stockholders' equity - Weighted Average Assumptions (Details)

v3.23.1
Stockholders' equity - Weighted Average Assumptions (Details) - Tecogen - Stock Options
12 Months Ended
Dec. 31, 2022
Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected life 6 years 3 months 6 years 3 months
Risk-free interest rate 2.17% 1.09%
Expected volatility 36.24% 35.86%