Marketable Securities - Components of Marketable Securities by Security Type (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Schedule Of Available For Sale Securities [Line Items]
Marketable Securities, Amortized Cost	$ 66,908	$ 101,050
Marketable Securities, Gross Unrealized Gains		14
Marketable Securities, Gross Unrealized Losses	(36)	(3)
Marketable Securities, Fair Value	66,872	101,061
U.S. Treasury Securities (due within one year) [Member]
Schedule Of Available For Sale Securities [Line Items]
Marketable Securities, Amortized Cost	63,907	74,066
Marketable Securities, Gross Unrealized Gains		10
Marketable Securities, Gross Unrealized Losses	(33)	(3)
Marketable Securities, Fair Value	63,874	74,073
U.S. Government Agency Bonds (due within one year) [Member]
Schedule Of Available For Sale Securities [Line Items]
Marketable Securities, Amortized Cost	3,001	26,984
Marketable Securities, Gross Unrealized Gains		4
Marketable Securities, Gross Unrealized Losses	(3)
Marketable Securities, Fair Value	$ 2,998	$ 26,988

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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