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Fair Value Measurements - Fair Values of Financial Assets Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	$ 130,426	$ 270,656
Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	11,910	82,008
Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	55,858	57,381
Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		2,474
Foreign government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		4,980
Convertible promissory note [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		1,000
Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	180,358	290,537
Fair Value, Measurements, Recurring [Member] | Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value disclosure	22,016	19,881
Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	11,910	82,008
Fair Value, Measurements, Recurring [Member] | Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	78,800	57,381
Fair Value, Measurements, Recurring [Member] | U.S. government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	62,665	111,345
Fair Value, Measurements, Recurring [Member] | Agency bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	4,967	11,468
Fair Value, Measurements, Recurring [Member] | Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		2,474
Fair Value, Measurements, Recurring [Member] | Foreign government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		4,980
Fair Value, Measurements, Recurring [Member] | Convertible promissory note [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		1,000
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	40,850	118,853
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value disclosure	22,016	19,881
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | U.S. government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	18,834	98,972
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Agency bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Foreign government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Convertible promissory note [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	139,508	170,684
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value disclosure	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	11,910	82,008
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	78,800	57,381
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | U.S. government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	43,831	12,373
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Agency bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	4,967	11,468
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		2,474
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Foreign government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		4,980
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Convertible promissory note [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value of financial assets	0	1,000
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value disclosure	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Corporate bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | U.S. government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Agency bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments	$ 0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Foreign government bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Convertible promissory note [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments		$ 1,000

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of 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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