Fair Value Measurements - Additional Information (Detail) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Fair Value Measurements, Non-recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liability measured and recognized at fair value	$ 0	$ 0
Fair Value Measurements, Non-recurring | Fair Value, Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Privately-held investments measured at fair value	348,000	348,000
Fair Value Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liability measured and recognized at fair value	$ 0	$ 0