Fair Value of Financial Assets - Fair Value of Financial Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Marketable securities:
Marketable securities	$ 66,872	$ 101,061
Cash equivalents and marketable securities	78,041	114,890
U.S. Treasury Securities (due within one year) [Member]
Marketable securities:
Marketable securities	63,874	74,073
U.S. Government Agency Bonds (due within one year) [Member]
Marketable securities:
Marketable securities	2,998	26,988
Money Market Funds [Member]
Cash equivalents:
Cash equivalents	11,169	13,829
Level 1 [Member]
Marketable securities:
Cash equivalents and marketable securities	11,169	13,829
Level 1 [Member] | Money Market Funds [Member]
Cash equivalents:
Cash equivalents	11,169	13,829
Level 2 [Member]
Marketable securities:
Cash equivalents and marketable securities	66,872	101,061
Level 2 [Member] | U.S. Treasury Securities (due within one year) [Member]
Marketable securities:
Marketable securities	63,874	74,073
Level 2 [Member] | U.S. Government Agency Bonds (due within one year) [Member]
Marketable securities:
Marketable securities	$ 2,998	$ 26,988