Investments

12 Months Ended

Dec. 31, 2020

Investments, Debt and Equity Securities [Abstract]

Investments

Investments

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

	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 (2)	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 (3)	$	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 we do not believe it is more likely than not that we will be required to sell these investments before recovery of their amortized cost bases.

(2)During the year ended December 31, 2020, we sold cash equivalent investments for proceeds of $27.1 million and realized no gain or loss on such sales.

(3)In January 2021, we increased our available-for-sale debt investments by approximately $60 million.

The following table summarizes the contractual maturities of our cash equivalents and available-for-sale debt investments as of December 31, 2020:

	Amortized Cost		Fair Value
Within 1 year	$	259,652	$	259,667
After 1 year through 5 years	14,705		14,713
After 5 years through 10 years	1,444		1,446
Total	$	275,801	$	275,826

Actual maturities can differ from contractual maturities due to various factors including whether the issuers have the right to call or prepay obligations without call or prepayment penalties, and we view our available-for-sale debt investments as available for current operations.

As of December 31, 2020, the amortized cost and the fair market value of our held-to-maturity government bond (Level 1) maturing within a year is $4.7 million.

The following table summarizes our debt investments as of December 31, 2019:

	December 31, 2019
	(In thousands)
Cash equivalent money market funds (Level 1) (1)	$	384,474
Short-term investment government bond (Level 2) (2)	6,348

(1)The cash equivalent money market funds (Level 1) at December 31, 2019 have been corrected to include $286.7 million of cash equivalents that were excluded in previously reported amounts. There was no change to total cash and cash equivalents reported on our consolidated balance sheet. We determined this was immaterial to the prior period but have presented the balance as revised for comparability.

(2)The fair market value of the security is $6.3 million.