Annual report [Section 13 and 15(d), not S-K Item 405]

Stockholders' equity - Weighted Average Assumptions (Details)

v3.25.1
Stockholders' equity - Weighted Average Assumptions (Details) - Tecogen - Stock Options
12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
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 4.28% 4.70%
Expected volatility 40.17% 38.49%
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Dividend Rate 0.00%