Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2020

Debt Securities, Available-for-sale [Abstract]

Cash equivalents and marketable securities classified as available-for-sale

Total cash, cash equivalents and marketable securities are summarized as follows:

	As of September 30, 2020
(In thousands)	Fair Value		Amortized  Cost		Gross  Unrealized  Gains		Gross  Unrealized  Losses		Weighted  Rate of  Return
Money market funds	$	25,123	$	25,123	$	—	$	—	0.04	%
U.S. Government bonds and notes	203,461		203,482		4		(25)		0.13	%
Corporate notes, bonds, commercial paper and other	232,785		232,857		15		(87)		0.21	%
Total cash equivalents and marketable securities	461,369		461,462		19		(112)
Cash	58,852		58,852		—		—
Total cash, cash equivalents and marketable securities	$	520,221	$	520,314	$	19	$	(112)

	As of December 31, 2019
(In thousands)	Fair Value		Amortized  Cost		Gross  Unrealized  Gains		Gross  Unrealized  Losses		Weighted  Rate of  Return
Money market funds	$	10,065	$	10,065	$	—	$	—	1.48	%
U.S. Government bonds and notes	39,086		39,087		—		(1)		1.49	%
Corporate notes, bonds, commercial paper and other	314,391		314,435		19		(63)		1.81	%
Total cash equivalents and marketable securities	363,542		363,587		19		(64)
Cash	44,122		44,122		—		—
Total cash, cash equivalents and marketable securities	$	407,664	$	407,709	$	19	$	(64)

Available-for-sale securities reported at fair value

Available-for-sale securities are reported at fair value on the balance sheets and classified as follows:

	As of
(In thousands)	September 30, 2020		December 31, 2019
Cash equivalents	$	30,623	$	58,054
Short term marketable securities	430,746		305,488
Total cash equivalents and marketable securities	461,369		363,542
Cash	58,852		44,122
Total cash, cash equivalents and marketable securities	$	520,221	$	407,664

Estimated fair value of cash equivalents and marketable securities classified by the length of time that the securities have been in a continuous unrealized loss position

The estimated fair value and gross unrealized losses of cash equivalents and marketable securities classified by the length of time that the securities have been in a continuous unrealized loss position at September 30, 2020 and December 31, 2019 are as follows:

	Fair Value				Gross Unrealized Loss
(In thousands)	September 30, 2020		December 31, 2019		September 30, 2020		December 31, 2019
Less than 12 months:
U.S. Government bonds and notes	$	61,419	$	14,112	$	(25)	$	(1)
Corporate notes, bonds, commercial paper and other	99,678		250,822		(87)		(63)
Total cash equivalents and marketable securities in a continuous unrealized loss position	$	161,097	$	264,934	$	(112)	$	(64)

Contractual maturities of cash equivalents (excluding money market funds which have no maturity) and marketable securities

The contractual maturities of cash equivalents (excluding money market funds which have no maturity) and marketable securities are summarized as follows:

(In thousands)	September 30, 2020
Due less than one year	$	379,932
Due from one year through three years	56,314
Total	$	436,246