Marketable Securities - Components of Marketable Securities by Security Type (Detail) - USD ($) $ in Thousands |
Sep. 30, 2021 |
Dec. 31, 2020 |
---|---|---|
Schedule Of Available For Sale Securities [Line Items] | ||
Marketable Securities, Amortized Cost | $ 80,359 | $ 101,050 |
Marketable Securities, Gross Unrealized Gains | 3 | 14 |
Marketable Securities, Gross Unrealized Losses | (2) | (3) |
Marketable Securities, Fair Value | 80,360 | 101,061 |
U.S. Treasury Securities (due within one year) [Member] | ||
Schedule Of Available For Sale Securities [Line Items] | ||
Marketable Securities, Amortized Cost | 77,358 | 74,066 |
Marketable Securities, Gross Unrealized Gains | 3 | 10 |
Marketable Securities, Gross Unrealized Losses | (2) | (3) |
Marketable Securities, Fair Value | 77,359 | 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, Fair Value | $ 3,001 | $ 26,988 |