Marketable Securities - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Marketable Securities [Line Items]
Marketable securities	$ 138,800,000		$ 405,600,000
Marketable securities unrealized loss, Less than twelve months	534,900,000		1,311,600,000
Marketable securities unrealized loss, more than twelve months	9,500,000		$ 4,600,000
Available-for-sale debt securities remaining maturities greater than thirty months	0
Other Comprehensive Income (Loss) [Member]
Marketable Securities [Line Items]
Unrealized loss, net	$ 11,800,000	$ 400,000