Annual report pursuant to Section 13 and 15(d)

Related party transactions (Details)

v3.19.1
Related party transactions (Details) - USD ($)
1 Months Ended 12 Months Ended
May 04, 2018
Mar. 27, 2018
Aug. 02, 2016
Jan. 31, 2017
Jul. 31, 2016
Dec. 31, 2018
Dec. 31, 2017
Sep. 30, 2017
May 19, 2016
Dec. 28, 2015
Related Party Transaction [Line Items]                    
Payment made to terminate senior convertible promissory note           $ 850,000 $ 3,150,000      
Equity interest in joint venture (percent)               43.00%    
Warrant exercise price per share (in dollars per share)         $ 4.00   $ 4.00      
Proceeds from exercise of warrants         $ 2,700,000          
Investments in joint venture               $ 13,500,000    
Return of investment in Ultra Emissions Technologies Ltd           0 $ 2,000,000      
Purchase of remaining assets of Ultratek           828,086 $ 580,044      
Affiliated companies                    
Related Party Transaction [Line Items]                    
Payments to acquire used equipment       $ 985,000            
Affiliated companies | TTcogen, LLC                    
Related Party Transaction [Line Items]                    
Revenue from related parties           347,275        
Due from related party           585,492        
Affiliated companies | Ultratek                    
Related Party Transaction [Line Items]                    
Return of investment in Ultra Emissions Technologies Ltd           2,000,000        
Purchase of remaining assets of Ultratek           400,000        
Co-venturer                    
Related Party Transaction [Line Items]                    
Investments in joint venture               8,500,000    
Ultra Emissions Technology Ltd.                    
Related Party Transaction [Line Items]                    
Equity interest in joint venture (percent)                   50.00%
TTcogen, LLC                    
Related Party Transaction [Line Items]                    
Equity interest in joint venture (percent)                 50.00%  
Offshore Investors                    
Related Party Transaction [Line Items]                    
Investment by other party to joint venture                   $ 3,000,000
Tedom a.s.                    
Related Party Transaction [Line Items]                    
Equity interest in joint venture (percent)                 50.00%  
Tedom USA                    
Related Party Transaction [Line Items]                    
Equity interest in joint venture (percent)                 50.00%  
Initial payment to acquire productive assets   $ 1                
Payments to acquire equity method investments   72,597                
Payments to acquire productive assets   $ 72,598                
Warrant                    
Related Party Transaction [Line Items]                    
Warrants exercised (shares)         675,000          
Warrant | Ultra Emissions Technology Ltd.                    
Related Party Transaction [Line Items]                    
Warrants exercised (shares)     2,000,000              
Warrant exercise price per share (in dollars per share)     $ 1.00              
Chief Executive Officer (John N. Hatsopoulos)                    
Related Party Transaction [Line Items]                    
Loan from related party           $ 850,000   $ 850,000    
Payment made to terminate senior convertible promissory note $ 919,590                  
Chief Executive Officer (John N. Hatsopoulos) | Demand notes                    
Related Party Transaction [Line Items]                    
Stated interest rate (percent)           6.00%   6.00%