Income Taxes - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Cumulative loss period	5 years
Reserve on US-based deferred tax amounts	$ 50,400,000
Outstanding tax audit		$ 0
State [Member]
Operating Loss Carryforwards [Line Items]
Federal income tax returns subject to examination description	State income tax returns are subject to examination for a period of three to four years after filing