Fair Value Measurements - Schedule of Reconciliation of Beginning and Ending Balance of Contingent Consideration Liability (Detail) - Contingent Consideration Liability [Member]	9 Months Ended
	Sep. 30, 2020 USD ($)
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2019	$ 2,750,000
Change in fair value	22,320,000
Balance at September 30, 2020	$ 25,070,000