Investment - Summary of Ranges and Weighted Averages of Significant Unobservable Inputs Used to Determine Enterprise Value (Detail) - Thesys Group, Inc [Member] - Preferred Stock [Member] - Level 3 [Member] - Income Approach Valuation Technique [Member]	12 Months Ended
	Dec. 31, 2019
Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Weighted average cost of capital ("WACC")	3.80%
Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Weighted average cost of capital ("WACC")	15.50%
Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Weighted average cost of capital ("WACC")	14.10%