Fair Value Measurements - Summary of Assumptions Used to Estimate Fair Value of Contingent Payments (Detail)	9 Months Ended
	Sep. 30, 2021
Minimum [Member] | Discount for Lack of Marketability [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	10
Maximum [Member] | Discount for Lack of Marketability [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	12
Level 3 [Member] | Expected Volatility [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	78.0
Level 3 [Member] | Risk-free Interest Rate [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	0.06
Level 3 [Member] | Cost of Capital [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	30
Level 3 [Member] | Probability of Payment [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	81
Level 3 [Member] | Minimum [Member] | Projected Year of Payment [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	2022
Level 3 [Member] | Weighted Average [Member] | Expected Volatility [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	78.0
Level 3 [Member] | Weighted Average [Member] | Risk-free Interest Rate [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	0.06
Level 3 [Member] | Weighted Average [Member] | Cost of Capital [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	30
Level 3 [Member] | Weighted Average [Member] | Discount for Lack of Marketability [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	11
Level 3 [Member] | Weighted Average [Member] | Probability of Payment [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	81
Level 3 [Member] | Weighted Average [Member] | Projected Year of Payment [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assumptions used to estimate fair value of contingent payments	2022