Cash and Investments in Marketable Securities - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Cash and Investments in Marketable Securities [Line Items]
Maximum maturity term for debt securities investment	2 years
Weighted average maturity term for debt securities investment (or less)	1 year
Gross Unrealized Gains		$ 1.1
Debt securities, available-for-sale accumulated gross unrealized loss, before tax		$ 0.2
Minimum
Cash and Investments in Marketable Securities [Line Items]
Long term investment maturity period	1 year
Maximum
Cash and Investments in Marketable Securities [Line Items]
Long term investment maturity period	2 years