Fair Value of Financial Instruments - Summary of Financial Instruments Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Liabilities
Contingent liability for Essentialis purchase price	$ 14,464	$ 11,549
Fair Value, Measurements, Recurring [Member]
Assets
Total cash equivalents	26,400
Total marketable securities	236,308
Total assets	262,708
Liabilities
Total liabilities	14,464	11,549
Fair Value, Measurements, Recurring [Member] \| Money Market Funds [Member]
Assets
Total cash equivalents	26,400
Fair Value, Measurements, Recurring [Member] \| US Treasury Securities [Member]
Assets
Total marketable securities	236,308
Essentialis, Inc. [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities
Contingent liability for Essentialis purchase price	14,464	11,549
Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Assets
Total cash equivalents	26,400
Total assets	26,400
Level 1 [Member] \| Fair Value, Measurements, Recurring [Member] \| Money Market Funds [Member]
Assets
Total cash equivalents	26,400
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Assets
Total marketable securities	236,308
Total assets	236,308
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member] \| US Treasury Securities [Member]
Assets
Total marketable securities	236,308
Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities
Total liabilities	14,464	11,549
Level 3 [Member] \| Essentialis, Inc. [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities
Contingent liability for Essentialis purchase price	$ 14,464	$ 11,549

Amount of liability recognized from contingent consideration in asset acquisition, classified as noncurrent.

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Fair value portion of asset recognized for present right to economic benefit.

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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), classified as current.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value of financial and nonfinancial obligations.

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