Assets and Liabilities Measured at Fair Value (Detail) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value		$ 46,851	$ 81,897
Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value	[1]	44,347	30,360
Fair Value, Inputs, Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value		46,851	68,197
Fair Value, Inputs, Level 1 | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value	[1]	44,347	30,360
Fair Value, Inputs, Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value			13,700
U.S. Government Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value	[2]	2,504	37,837
U.S. Government Agency Securities | Fair Value, Inputs, Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value	[2]	$ 2,504	37,837
Short-Term Investments | Federal Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value	[2]		13,700
Short-Term Investments | Fair Value, Inputs, Level 2 | Federal Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value	[2]		$ 13,700

[1] Included in cash and cash equivalents on accompanying consolidated balance sheet.

[2] Included in short-term investments on accompanying consolidated balance sheet and are classified as available-for-sale debt securities. $2.5 million of U.S. government agency securities as of December 31, 2020 are included in long-term investments on the accompanying consolidated balance sheets due to the maturity being more than 12 months.