Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Fair Value on a Recurring Basis (Details)

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Fair Value Measurements - Fair Value on a Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($)
3 Months Ended 12 Months Ended
Mar. 31, 2018
Dec. 31, 2017
May 18, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Total gains (losses) $ (184,998)    
Level 1      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Total recurring fair value measurements 0    
Level 2      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Total recurring fair value measurements 334,570    
Level 3      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Total recurring fair value measurements 0    
Estimate of Fair Value Measurement      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Total recurring fair value measurements 334,570    
Eurosite Power Inc      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Total gains (losses) (184,998) $ (165,317)  
Eurosite Power Inc | Level 1      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale equity securities 0    
Eurosite Power Inc | Level 2      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale equity securities 334,570 $ 354,251 $ 519,568
Eurosite Power Inc | Level 3      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale equity securities 0    
Eurosite Power Inc | Estimate of Fair Value Measurement      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Available-for-sale equity securities $ 334,570