Investments (Tables)

9 Months Ended

Sep. 30, 2021

Investments, Debt and Equity Securities [Abstract]

Summary of debt securities available-for-sale

The following table summarizes our cash equivalents and available-for-sale debt investments:

	September 30, 2021
									Fair Value Level
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses (1)		Total Fair Value		Level 1		Level 2
	(In thousands)
Cash equivalents
Asset-backed securities	$	4	$	—	$	—	$	4	$	—	$	4
Commercial paper	16,757		—		—		16,757		—		16,757
Corporate bonds	5,908		—		(1)		5,907		—		5,907
Money market funds	143,262		—		—		143,262		143,262		—
Total cash equivalents	165,931		—		(1)		165,930		143,262		22,668
Short-term investments
Asset-backed securities	23,155		2		(4)		23,153		—		23,153
Certificate of deposits	18,381		—		—		18,381		18,381		—
Commercial paper	23,112		—		—		23,112		—		23,112
Corporate bonds	156,405		11		(165)		156,251		—		156,251
Municipal bonds	14,072		1		(1)		14,072		—		14,072
U.S. government bonds	4,120		—		(1)		4,119		4,119		—
Variable rate demand notes	700		—		—		700		—		700
Total short-term investments	239,945		14		(171)		239,788		22,500		217,288
Total	$	405,876	$	14	$	(172)	$	405,718	$	165,762	$	239,956

	December 31, 2020
									Fair Value Level
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses (1)		Total Fair Value		Level 1		Level 2
	(In thousands)
Cash equivalents
Certificate of deposits	$	976	$	—	$	—	$	976	$	976	$	—
Commercial paper	5,293		—		—		5,293		—		5,293
Corporate bonds	1,744		—		—		1,744		—		1,744
Money market funds	138,290		—		—		138,290		138,290		—
Municipal bonds	400		—		—		400		—		400
Total cash equivalents	146,703		—		—		146,703		139,266		7,437
Short-term investments
Asset-backed securities	19,111		18		(9)		19,120		—		19,120
Certificate of deposits	5,046		—		—		5,046		5,046		—
Commercial paper	15,148		—		—		15,148		—		15,148
Corporate bonds	50,771		16		(12)		50,775		—		50,775
Municipal bonds	12,702		8		(2)		12,708		—		12,708
U.S. government agency bonds	8,415		3		—		8,418		—		8,418
U.S. government bonds	17,605		3		—		17,608		17,608		—
Variable rate demand notes	300		—		—		300		—		300
Total short-term investments	129,098		48		(23)		129,123		22,654		106,469
Total	$	275,801	$	48	$	(23)	$	275,826	$	161,920	$	113,906

(1)All unrealized losses have been in a continuous loss position for less than 12 months. We do not intend to sell the investments in an unrealized loss position, and it is not more likely than not that we will be required to sell these investments before recovery of their amortized cost bases.

The following table summarizes the contractual maturities of our cash equivalents and available-for-sale debt investments as of September 30, 2021:

	Amortized Cost		Fair Value
	(In thousands)
Within 1 year	$	320,948	$	320,877
After 1 year through 5 years	82,992		82,905
After 5 years through 10 years	406		406
After 10 years	1,530		1,530
Total	$	405,876	$	405,718