FAIR VALUE MEASUREMENTS (Tables)

9 Months Ended

Sep. 30, 2021

Schedule of cash equivalents, restricted cash and marketable securities by security type

Cash equivalents, restricted cash and marketable securities by security type at September 30, 2021 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	$	19,805	$	—	$	—		$	19,805
Commercial paper		5,000		—		—			5,000
	$	24,805	$	—	$	—		$	24,805

Restricted cash:
Money market fund	$	92	$	—	$	—		$	92
Certificate of deposit		271		—		—			271
	$	363	$	—	$	—		$	363

Marketable securities:
U.S. Treasury securities (due in less than one year)	$	14,056	$	3	$	—		$	14,059
U.S. Treasury securities (due in one to two years)		7,099		2		—			7,101
Municipal securities (due in one to two years)		3,000		—		(1	)		2,999
Government-sponsored enterprise securities (due in less than one year)		11,250		2		—			11,252
Government-sponsored enterprise securities (due in one to two years)		5,000		—		(3	)		4,997
Commercial paper (due in less than one year)		72,440		10		(10	)		72,440
Corporate notes (due in less than one year)		49,309		32		(8	)		49,333
Corporate notes (due in one to two years)		24,276		5		(16	)		24,265
	$	186,430	$	54	$	(38	)	$	186,446

Cash equivalents, restricted cash and marketable securities by security type at December 31, 2020 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	$	4,356	$	—	$	—		$	4,356

Restricted cash:
Money market fund	$	92	$	—	$	—		$	92
Certificate of deposit		271		—		—			271
	$	363	$	—	$	—		$	363

Marketable securities:
U.S. Treasury securities (due in less than one year)	$	5,608	$	2	$	—		$	5,610
U.S. Treasury securities (due in one to two years)		5,093		2		—			5,095
Government-sponsored enterprise securities (due in less than one year)		5,249		3		—			5,252
Government-sponsored enterprise securities (due in one to two years)		23,499		7		(1	)		23,505
Commercial paper (due in less than one year)		112,388		29		(8	)		112,409
Corporate notes (due in less than one year)		63,051		35		(7	)		63,079
Corporate notes (due in one to two years)		34,771		33		(17	)		34,787
	$	249,659	$	111	$	(33	)	$	249,737

Schedule of cash equivalents and marketable securities with unrealized losses

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, 2021 and December 31, 2020 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, 2021:
Municipal securities (due in one to two years)	$	2,999	$	(1	)	$	—	$	—	$	2,999		(1	)
Government-sponsored enterprise securities (due in one to two years)		4,997		(3	)		—		—		4,997		(3	)
Commercial paper (due in less than one year)		31,965		(10	)		—		—		31,965		(10	)
Corporate notes (due in less than one year)		17,252		(8	)		—		—		17,252		(8	)
Corporate notes (due in one to two years)		15,232		(16	)		—		—		15,232		(16	)
	$	72,445	$	(38	)	$	—	$	—	$	72,445	$	(38	)

As of December 31, 2020:
Government-sponsored enterprise securities (due in one to two years)	$	4,999	$	(1	)	$	—	$	—	$	4,999	$	(1	)
Commercial paper (due in less than one year)		22,956		(8	)		—		—		22,956		(8	)
Corporate notes (due in less than one year)		12,573		(7	)		—		—		12,573		(7	)
Corporate notes (due in one to two years)		16,322		(17	)		—		—		16,322		(17	)
	$	56,850	$	(33	)	$	—	$	—	$	56,850	$	(33	)

Schedule of financial instruments measured at fair value on recurring basis

The following table presents information about our financial instruments that are measured at fair value on a recurring basis as of September 30, 2021 and December 31, 2020 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, 2021:
Money market funds⁽¹⁾	$	19,805	$	—	$	—	$	19,805
U.S. Treasury securities⁽²⁾⁽³⁾		—		21,160		—		21,160
Municipal securities⁽³⁾		—		2,999		—		2,999
Government-sponsored enterprise securities⁽²⁾⁽³⁾		—		16,249		—		16,249
Commercial paper⁽¹⁾⁽²⁾		—		77,440		—		77,440
Corporate notes⁽²⁾⁽³⁾		—		73,598		—		73,598
Total	$	19,805	$	191,446	$	—	$	211,251
As of December 31, 2020:
Money market funds⁽¹⁾	$	4,356	$	—	$	—	$	4,356
U.S. Treasury securities⁽²⁾⁽³⁾		—		10,705		—		10,705
Government-sponsored enterprise securities⁽²⁾⁽³⁾		—		28,757		—		28,757
Commercial paper⁽²⁾		—		112,409		—		112,409
Corporate notes⁽²⁾⁽³⁾		—		97,866		—		97,866
Equity investment⁽⁴⁾		—		361		—		361
Total	$	4,356	$	250,098	$	—	$	254,454

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

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

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

(4)	Included in deposits and other assets on our condensed balance sheets. See “Equity Investment” in this Note 2 for further discussion of this equity investment.