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 ($)
Jun. 30, 2021
Dec. 31, 2020
Jun. 30, 2020
Dec. 31, 2019
Level 1        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Total recurring fair value measurements $ 0   $ 0  
Level 2        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Available-for-sale equity securities   $ 118,084 118,084 $ 216,487
Total recurring fair value measurements 168,739   118,084  
Level 3        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Total recurring fair value measurements 0   0  
Estimate of Fair Value Measurement        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Total recurring fair value measurements 168,739   118,084  
Eurosite Power, Inc. | Level 1        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Available-for-sale equity securities 0   0  
Eurosite Power, Inc. | Level 2        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Available-for-sale equity securities 168,739   118,084  
Eurosite Power, Inc. | Level 3        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Available-for-sale equity securities 0   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 $ 168,739   $ 118,084