Summary of Cash, Cash Equivalents and Restricted Cash Reported In Condensed Consolidated Statements of Cash Flows (Parenthetical) (Detail)	9 Months Ended
	Sep. 30, 2020
Minimum
Cash And Cash Equivalents Period Increase Decrease [Line Items]
Short -term cash investments interest rate	0.06%
Maximum
Cash And Cash Equivalents Period Increase Decrease [Line Items]
Short -term cash investments interest rate	0.31%