Marketable Securities (Tables)

3 Months Ended

Mar. 31, 2020

Debt Securities, Available-for-sale [Abstract]

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

All cash equivalents and marketable securities are classified as available-for-sale. Total cash, cash equivalents and marketable securities are summarized as follows:

	As of March 31, 2020
(In thousands)	Fair Value		Amortized  Cost		Gross  Unrealized  Gains		Gross  Unrealized  Losses			Weighted  Rate of  Return
Money market funds	$	22,143	$	22,143	$	—	$	—		0.32	%
U.S. Government bonds and notes	44,247		44,135		112		—			1.20	%
Corporate notes, bonds, commercial paper and other	323,639		323,892		47		(300		)	1.61	%
Total cash equivalents and marketable securities	390,029		390,170		159		(300		)
Cash	45,416		45,416		—		—
Total cash, cash equivalents and marketable securities	$	435,445	$	435,586	$	159	$	(300	)

	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)	March 31, 2020		December 31, 2019
Cash equivalents	$	130,030	$	58,054
Short term marketable securities	259,999		305,488
Total cash equivalents and marketable securities	390,029		363,542
Cash	45,416		44,122
Total cash, cash equivalents and marketable securities	$	435,445	$	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 of cash equivalents and marketable securities classified by the length of time that the securities have been in a continuous unrealized loss position at March 31, 2020 and December 31, 2019 are as follows:

	Fair Value				Gross Unrealized Loss
(In thousands)	March 31, 2020		December 31, 2019		March 31, 2020			December 31, 2019
Less than one year
U.S. Government bonds and notes	$	—	$	14,112	$	—		$	(1	)
Corporate notes, bonds and commercial paper	182,702		250,822		(300		)	(63		)
Total Corporate notes, bonds, and commercial paper and U.S. Government bonds and notes	$	182,702	$	264,934	$	(300	)	$	(64	)