Quarterly report pursuant to Section 13 or 15(d)

Related party transactions (Details)

v3.8.0.1
Related party transactions (Details)
 1 Months Ended 9 Months Ended
Aug. 02, 2016
USD ($)
$ / shares
shares
Jan. 31, 2017
USD ($)
Jul. 31, 2016
USD ($)
$ / shares
shares
Sep. 30, 2017
USD ($)
company
Sep. 30, 2016
USD ($)
May 19, 2016
Dec. 28, 2015
USD ($)
Schedule of Equity Method Investments [Line Items]              
Number of affiliated companies | company       2      
Equity interest in joint venture (percent)       43.00%      
Warrant exercise price (per share) | $ / shares     $ 4.00        
Proceeds from exercise of warrants     $ 2,700,000 $ 0 $ 2,700,000    
Investments in joint venture       13,500,000      
Ultra Emissions Technology Ltd.              
Schedule of Equity Method Investments [Line Items]              
Equity interest in joint venture (percent)             50.00%
Warrants exercised for investment in joint venture $ 2,000,000            
Due from affiliate       94,777      
TTcogen, LLC              
Schedule of Equity Method Investments [Line Items]              
Equity interest in joint venture (percent)           50.00%  
Due from affiliate       391,618      
Offshore Investors              
Schedule of Equity Method Investments [Line Items]              
Investment by other party to joint venture             $ 3,000,000
Tedom a.s.              
Schedule of Equity Method Investments [Line Items]              
Equity interest in joint venture (percent)           50.00%  
Warrant              
Schedule of Equity Method Investments [Line Items]              
Warrants exercised (shares) | shares     675,000        
Warrant | Ultra Emissions Technology Ltd.              
Schedule of Equity Method Investments [Line Items]              
Warrants exercised (shares) | shares 2,000,000            
Warrant exercise price (per share) | $ / shares $ 1.00            
American DG Energy              
Schedule of Equity Method Investments [Line Items]              
Equipment purchase   $ 985,000          
Co-venturer              
Schedule of Equity Method Investments [Line Items]              
Investments in joint venture       8,500,000      
Co-Chief Executive Officer              
Schedule of Equity Method Investments [Line Items]              
Loan from related party       $ 850,000      
Notes Payable | Co-Chief Executive Officer              
Schedule of Equity Method Investments [Line Items]              
Stated interest rate (percent)       6.00%