Investments and Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2021

Investments and Fair Value Measurements

Schedule of available-for-sale securities

		September 30, 2021
				Gross		Gross
		Amortized		Unrealized		Unrealized		Estimated
(In thousands)		Cost		Gains		Losses		Fair Value
US government securities	Level 1	$	5,000	$	—	$	—	$	5,000
Corporate notes	Level 2		4,800		6		—		4,806
Commercial paper	Level 2		94,978		4		—		94,982
Marketable securities			104,778		10		—		104,788
Money market funds	Level 1		80,836		—		—		80,836
Total		$	185,614	$	10	$	—	$	185,624

		December 31, 2020
				Gross		Gross
		Amortized		Unrealized		Unrealized		Estimated
(In thousands)		Cost		Gains		Losses		Fair Value
US government securities	Level 1	$	75,036	$	34	$	—	$	75,070
US government agency securities	Level 2		74,971		18		—		74,989
Corporate notes	Level 2		5,046		—		(1)		5,045
Commercial paper	Level 2		56,374		1		(5)		56,370
Marketable securities			211,427		53		(6)		211,474
Money market funds	Level 1		—		—		—		—
Total		$	211,427	$	53	$	(6)	$	211,474

Schedule of Available for sale debt securities with unrealized losses

	December 31, 2020
	Less than 12 Months				Greater than 12 Months				Total
			Gross				Gross				Gross
	Estimated		Unrealized		Estimated		Unrealized		Estimated		Unrealized
(In thousands)	Fair Value		Losses		Fair Value		Losses		Fair Value		Losses
Corporate notes	$	5,045	$	(1)	$	—	$	—	$	5,045	$	(1)
Commercial paper		39,375		(5)		—		—		39,375		(5)
Total	$	44,420	$	(6)	$	—	$	—	$	44,420	$	(6)