Quarterly report pursuant to Section 13 or 15(d)

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

Fair Value Measurements - Fair Value on a Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($)	Sep. 30, 2021	Dec. 31, 2020	Sep. 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	131,242	$ 118,084	118,084	$ 216,487
Total recurring fair value measurements	131,242		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	131,242		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	131,242		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	$ 131,242		$ 118,084