Annual report pursuant to Section 13 and 15(d)

Stockholders' equity - Weighted Average Assumptions (Details)

v2.4.0.8
Stockholders' equity - Weighted Average Assumptions (Details) (Stock options)
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Tecogen
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected life 5 years 7 months 18 days 6 years 3 months
Risk-free interest rate 1.34% 0.70%
Expected volatility, Minimum 26.50% 35.90%
Expected volatility, Maximum 36.00% 36.00%
Ilois
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected life   6 years 3 months
Risk-free interest rate   2.03%
Expected volatility   36.10%