FAIR VALUE MEASUREMENTS

9 Months Ended

Sep. 30, 2023

Fair Value Disclosures [Abstract]

FAIR VALUE MEASUREMENTS

2. FAIR VALUE MEASUREMENTS

Cash Equivalents and Marketable Securities

Cash equivalents, restricted cash and marketable securities by security type at September 30, 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	$	12,549	$	—	$	—		$	12,549
Commercial Paper		3,970		—		—			3,970
	$	16,519	$	—	$	—		$	16,519
Restricted cash:
Money market fund	$	264	$	—	$	—		$	264
Certificate of deposit		272		—		—			272
	$	536	$	—	$	—		$	536
Marketable securities:
U.S. Treasury securities - due in 1 to 2 years	$	26,467	$	1	$	(22	)	$	26,446
Government-sponsored enterprise    securities (due in less than one year)		94,524		4		(293	)		94,235
Government-sponsored enterprise    securities (due in one to two years)		10,651		—		(35	)		10,616
Commercial paper (due in less than    one year)		149,583		1		(280	)		149,304
Corporate notes (due in less than one year)		39,438		2		(160	)		39,280
Corporate notes (due in one to two years)		30,939		1		(182	)		30,758
	$	351,602	$	9	$	(972	)	$	350,639

Cash equivalents, restricted cash and marketable securities by security type at December 31, 2022 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	$	39,771	$	—	$	—		$	39,771
	$	39,771	$	—	$	—		$	39,771
Restricted cash:
Money market fund	$	93	$	—	$	—		$	93
Certificate of deposit		271		—		—			271
	$	364	$	—	$	—		$	364
Marketable securities:
U.S. Treasury securities (due in    less than one year)	$	12,983	$	—	$	(62	)	$	12,921
Municipal securities (due in    less than one year)		3,000		—		(24	)		2,976
Government-sponsored enterprise securities    (due in less than one year)		9,860		—		(14	)		9,846
Commercial paper (due in less than    one year)		64,285		6		(92	)		64,199
Corporate notes (due in less than one year)		26,014		—		(55	)		25,959
	$	116,142	$	6	$	(247	)	$	115,901

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 September 30, 2023 and December 31, 2022 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 September 30, 2023:
US Treasury Securities (due in less than one year)	$	26,446	$	(22	)	$	—	$	—		$	26,446	$	(22	)
Government-sponsored enterprise    securities (due in less than one year)		94,523		(293	)		—		—			94,523		(293	)
Government-sponsored enterprise    securities (due in one to two years)		10,651		(35	)		—		—			10,651		(35	)
Commercial paper (due in less than    one year)		149,584		(281	)		—		—			149,584		(281	)
Corporate notes (due in less than    one year)		39,438		(160	)		—		—			39,438		(160	)
Corporate notes (due in one to    two years)		30,939		(181	)		—		—			30,939		(181	)
	$	351,581	$	(972	)	$	—	$	—		$	351,581	$	(972	)
As of December 31, 2022:
U.S. Treasury securities (due in less than one year)	$	11,424	$	(57	)	$	1,497	$	(5	)	$	12,921	$	(62	)
Municipal securities    (due in less than a year)		—		—			2,976		(24	)		2,976		(24	)
Government-sponsored    enterprise securities    (due in less than one year)		9,845		(14	)		—		—			9,845		(14	)
Commercial paper (due in less than    one year)		52,454		(92	)		—		—			52,454		(92	)
Corporate notes (due in    less than one year)		1,998		(2	)		23,962		(53	)		25,960		(55	)
	$	75,721	$	(165	)	$	28,435	$	(82	)	$	104,156	$	(247	)

The gross unrealized losses related to U.S. Treasury securities, municipal securities, government-sponsored enterprise securities, commercial paper and corporate notes as of September 30, 2023 and December 31, 2022 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 nine months ended September 30, 2023 and 2022 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 September 30, 2023 and December 31, 2022 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 September 30, 2023:
Money market funds(1)(2)	$	12,813	$	—	$	—	$	12,813
Certificate of deposit(2)		272		—		—		272
U.S. Treasury securities(3)		—		26,446		—		26,446
Government-sponsored enterprise    securities(3)(4)		—		104,852		—		104,852
Commercial paper(3)		—		153,274		—		153,274
Corporate notes(3)(4)		—		70,037		—		70,037
Total	$	13,085	$	354,609	$	—	$	367,694
As of December 31, 2022:
Money market funds(1)(2)	$	39,864	$	—	$	—	$	39,864
Certificate of deposit(2)		271		—		—		271
U.S. Treasury securities(3)		—		12,921		—		12,921
Municipal securities(3)		—		2,976		—		2,976
Government-sponsored enterprise    securities(2)		—		9,846		—		9,846
Commercial paper(3)		—		64,199		—		64,199
Corporate notes(3)		—		25,959		—		25,959
Total	$	40,135	$	115,901	$	—	$	156,036

(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.