Cash Equivalents, Restricted Cash and Investments - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2021 USD ($) Investment	Dec. 31, 2020 USD ($)
Cash And Cash Equivalents [Abstract]
Maturity period available-for-sale securities	less than two years
Significant realized gains or losses on available-for-sale securities	$ 0
Cash	$ 4,500,000	$ 2,200,000
Number of available-for-sale securities in a continuous unrealized loss position for more than 12 months | Investment	0