Quarterly report pursuant to Section 13 or 15(d)

Related party transactions (Details)

v3.5.0.2
Related party transactions (Details)
 1 Months Ended 9 Months Ended
Aug. 02, 2016
USD ($)
$ / shares
shares
Jul. 31, 2016
USD ($)
$ / shares
shares
Sep. 30, 2016
USD ($)
company
Sep. 30, 2015
USD ($)
May 19, 2016
Dec. 31, 2015
USD ($)
Dec. 28, 2015
USD ($)
Schedule of Equity Method Investments [Line Items]              
Number of affiliated companies | company     2        
Investment by other party to joint venture     $ 2,000,000     $ 0  
Warrant exercise price (per share) | $ / shares   $ 4.00          
Proceeds from the exercise of warrants   $ 2,700,000 $ 2,700,000 $ 0      
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            
TTcogen, LLC              
Schedule of Equity Method Investments [Line Items]              
Equity interest in joint venture (percent)         50.00%    
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