Fair Value of Financial Instruments - Investments Categorization in Fair Value Hierarchy (Detail) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 144,195,000	$ 82,500,000
Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0
Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0
Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	144,195,000
Total Senior Secured Notes
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	48,167,603	30,700,000
Total Senior Secured Notes | Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0
Total Senior Secured Notes | Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0
Total Senior Secured Notes | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	48,167,603
Equity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	96,027,397	$ 51,800,000
Equity | Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0
Equity | Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0
Equity | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 96,027,397