Fair Value of Financial Instruments - Investments Categorization in Fair Value Hierarchy (Detail) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 163,301,338	$ 144,195,000
Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0	0
Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0	0
Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	163,301,338	144,195,000
Total Senior Secured Notes
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	53,642,454	48,167,603
Total Senior Secured Notes | Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0	0
Total Senior Secured Notes | Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0	0
Total Senior Secured Notes | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	53,642,454	48,167,603
Equity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	109,658,884	96,027,397
Equity | Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0	0
Equity | Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	0	0
Equity | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 109,658,884	$ 96,027,397