FAIR VALUE MEASUREMENTS

6 Months Ended

Jun. 30, 2024

Fair Value Disclosures [Abstract]

FAIR VALUE MEASUREMENTS

4. FAIR VALUE MEASUREMENTS

Cash Equivalents and Marketable Securities

Cash equivalents, restricted cash and marketable securities by security type at June 30, 2024 were as follows:

			Gross		Gross
	Amortized		Unrealized		Unrealized			Estimated
(In thousands)	Cost		Gains		Losses			Fair Value
Included in cash and cash equivalents:
Money market funds	$	74,801	$	—	$	—		$	74,801
	$	74,801	$	—	$	—		$	74,801
Restricted cash:
Money market fund	$	850	$	—	$	—		$	850
Certificate of deposit		273		—		—			273
	$	1,123	$	—	$	—		$	1,123
Marketable securities:
U.S. Treasury securities (due in    less than one year)	$	39,885	$	—	$	(30	)	$	39,855
Government-sponsored enterprise    securities (due in less than one year)		44,532		2		(44	)		44,490
Government-sponsored enterprise securities    (due in one to two years)		5,000		—		(9	)		4,991
Commercial paper (due in less than    one year)		110,400		1		(192	)		110,209
Corporate notes (due in less than one year)		51,347		3		(115	)		51,235
Corporate notes (due in one to two years)		61,630		5		(121	)		61,514
	$	312,794	$	11	$	(511	)	$	312,294

Cash equivalents, restricted cash and marketable securities by security type at December 31, 2023 were as follows:

			Gross		Gross
	Amortized		Unrealized		Unrealized			Estimated
(In thousands)	Cost		Gains		Losses			Fair Value
Included in cash and cash equivalents:
Money market funds	$	16,815	$	—	$	—		$	16,815
	$	16,815	$	—	$	—		$	16,815
Restricted cash:
Money market fund	$	843	$	—	$	—		$	843
Certificate of deposit		272		—		—			272
	$	1,115	$	—	$	—		$	1,115
Marketable securities:
U.S. Treasury securities (due in    less than one year)	$	26,752	$	95	$	—		$	26,847
U.S. Treasury securities (due in  one to two years)		2,877		17		—			2,894
Government-sponsored enterprise securities    (due in less than one year)		86,250		43		(92	)		86,201
Government-sponsored enterprise securities    (due in one to two years)		13,598		72		—			13,670
Commercial paper (due in less than    one year)		102,270		31		(33	)		102,268
Corporate notes (due in less than one year)		48,409		14		(63	)		48,360
Corporate notes (due in one to two years)		26,628		130		(24	)		26,734
	$	306,784	$	402	$	(212	)	$	306,974

Cash equivalents and marketable securities with unrealized losses that have been in a continuous unrealized loss position for less than 12 months and 12 months or longer at June 30, 2024 and December 31, 2023 were as follows:

	Less Than 12 Months					12 Months or Longer					Total
			Gross					Gross					Gross
	Estimated		Unrealized			Estimated		Unrealized			Estimated		Unrealized
(In thousands)	Fair Value		Losses			Fair Value		Losses			Fair Value		Losses
As of June 30, 2024:
US Treasury Securities (due in less than    one year)	$	39,855	$	(30	)	$	—	$	—		$	39,855	$	(30	)
Government-sponsored enterprise    securities (due in less than one year)		30,562		(19	)		13,928		(25	)		44,490		(44	)
Government-sponsored enterprise    securities (due in one to two years)		4,991		(9	)		—		—			4,991		(9	)
Commercial paper (due in less than    one year)		110,209		(192	)		—		—			110,209		(192	)
Corporate notes (due in less than    one year)		40,815		(76	)		10,420		(39	)		51,235		(115	)
Corporate notes (due in one to    two years)		61,514		(121	)		—		—			61,514		(121	)
	$	287,946	$	(447	)	$	24,348	$	(64	)	$	312,294	$	(511	)
As of December 31, 2023:
Government-sponsored enterprise    securities (due in less than one year)	$	69,377	$	(92	)	$	—	$	—		$	69,377		(92	)
Commercial paper (due in less than    one year)		58,622		(33	)		—		—			58,622		(33	)
Corporate notes (due in    less than one year)		34,567		(63	)		—		—			34,567		(63	)
Corporate notes (due in    one to two years)		3,952		(23	)		—		—			3,952		(23	)
	$	166,518	$	(211	)	$	—	$	—		$	166,518	$	(211	)

The gross unrealized losses related to U.S. Treasury securities, municipal securities, government-sponsored enterprise securities, commercial paper and corporate notes as of June 30, 2024 and December 31, 2023 were due to changes in interest rates and not credit risk. If an available-for-sale security’s fair value is less than its amortized cost basis, we evaluate whether the decline is the result of a credit loss, in which case an impairment is recorded through an allowance for credit losses. We have not recorded any allowances for credit losses on our available-for-sale securities for the three and six months ended June 30, 2024 and 2023 as we have not identified any unrealized losses for these securities attributable to credit factors. Our exposure to unrealized losses may increase in the future due to the economic pressures or uncertainties associated with macroeconomic or other global economic conditions, including those resulting from inflation, rising interest rates, prospects of a recession, bank failures and other disruptions to financial systems, civil or political unrest, military conflicts, pandemics or other health crises.

Fair Value on a Recurring Basis

We categorize financial instruments recorded at fair value on our condensed consolidated balance sheets based upon the level of judgment associated with inputs used to measure their fair value. The categories are as follows:

Level 1	—	Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date. An active market for an asset or liability is a market in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis.
Level 2	—	Inputs (other than quoted market prices included in Level 1) are either directly or indirectly observable for the asset or liability through correlation with market data at the measurement date and for the duration of the instrument’s anticipated life.
Level 3	—	Inputs reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date. Consideration is given to the risk inherent in the valuation technique and the risk inherent in the inputs to the model.

A financial instrument’s categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. Money market funds are categorized as Level 1 within the fair value hierarchy as their fair values are based on quoted prices available in active markets. U.S. Treasury securities, municipal securities, government-sponsored enterprise securities, commercial paper, and corporate notes are categorized as Level 2 within the fair value hierarchy as their fair values are estimated by using pricing models, quoted prices of securities with similar characteristics or discounted cash flows.

The following table presents information about our financial instruments that are measured at fair value on a recurring basis as of June 30, 2024 and December 31, 2023 and indicates the fair value category assigned.

	Fair Value Measurements at Reporting Date Using
	Quoted Prices in				Significant
	Active Markets for		Significant Other		Unobservable
	Identical Assets		Observable Inputs		Inputs
(In thousands)	Level 1		Level 2		Level 3		Total
As of June 30, 2024:
Money market funds(1)(2)	$	75,651	$	—	$	—	$	75,651
Certificate of deposit(2)		273		—		—		273
U.S. Treasury securities(3)		—		39,855		—		39,855
Government-sponsored enterprise    securities(3)(4)		—		49,481		—		49,481
Commercial paper(3)		—		110,209		—		110,209
Corporate notes(3)(4)		—		112,748		—		112,748
Total	$	75,924	$	312,293	$	—	$	388,217
As of December 31, 2023:
Money market funds(1)(2)	$	17,658	$	—	$	—	$	17,658
Certificate of deposit(2)		272		—		—		272
U.S. Treasury securities(3)(4)		—		29,742		—		29,742
Government-sponsored enterprise    securities(3)(4)		—		99,872		—		99,872
Commercial paper(3)		—		102,268		—		102,268
Corporate notes(3)(4)		—		75,092		—		75,092
Total	$	17,930	$	306,974	$	—	$	324,904

(1)Included in cash and cash equivalents on our condensed consolidated balance sheets.

(2)Included in restricted cash on our condensed consolidated balance sheets.

(3)Included in current portion of marketable securities on our condensed consolidated balance sheets.

(4)Included in noncurrent portion of marketable securities on our condensed consolidated balance sheets.