Marketable Securities

6 Months Ended

Jun. 30, 2018

Marketable Securities

Marketable Securities

5. Marketable Securities

The Company’s marketable securities held as of June 30, 2018 and December 31, 2017 are summarized below:

			Gross		Gross
	Amortized		Unrealized		Unrealized
June 30, 2018	Cost		Gains		Losses		Fair Value
(in thousands)
Money Market Funds	$	31,144	$	—	$	—	$	31,144
Corporate Securities		96,756		—		(654)		96,102
Government Securities		425,329		21		(1,365)		423,985
	$	553,229	$	21	$	(2,019)	$	551,231
Reported as
Cash and cash equivalents							$	31,144
Marketable securities								520,087
Total investments							$	551,231
			Gross		Gross
	Amortized		Unrealized		Unrealized
December 31, 2017	Cost		Gains		Losses		Fair Value
(in thousands)
Money Market Funds	$	5,175	$	—	$	—	$	5,175
Corporate Securities		123,860		—		(590)		123,270
Government Securities		224,739		—		(1,209)		223,530
	$	353,774	$	—	$	(1,799)	$	351,975
Reported as
Cash and cash equivalents							$	5,175
Marketable securities								346,800
Total investments							$	351,975

The maturities of the Company’s marketable securities are as follows:

	Amortized		Estimated
June 30, 2018	Cost		Fair Value
(in thousands)
Mature in one year or less	$	221,286	$	220,116
Mature within two years		300,799		299,971
	$	522,085	$	520,087

The unrealized losses on available-for-sale investments and their related fair values as of June 30, 2018 and December 31, 2017 are as follows:

	Less than 12 months				12 months or greater
June 30, 2018		Fair value		Unrealized losses		Fair value		Unrealized losses
(in thousands)
Corporate Securities	$	63,850	$	(475)	$	32,252	$	(179)
Government Securities		156,266		(695)		267,719		(670)
	$	220,116	$	(1,170)	$	299,971	$	(849)
	Less than 12 months				12 months or greater
December 31, 2017		Fair value		Unrealized losses		Fair value		Unrealized losses
(in thousands)
Corporate Securities	$	79,290	$	(137)	$	43,980	$	(453)
Government Securities		128,313		(461)		95,217		(748)
	$	207,603	$	(598)	$	139,197	$	(1,201)

The unrealized losses from the listed securities are due to a change in the interest rate environment and not a change in the credit quality of the securities.