Marketable Securities

6 Months Ended

Jun. 30, 2015

Marketable Securities [Abstract]

MARKETABLE SECURITIES

MARKETABLE SECURITIES

The Company manages its cash equivalents and marketable securities as a single investment portfolio that is intended to be available to meet the Company’s current cash requirements. Cash equivalents consist primarily of investments in money market funds. Marketable securities, which the Company classifies as available-for-sale securities, primarily consist of high quality commercial paper, corporate bonds, and U.S. government debt obligations. Marketable securities with remaining effective maturities of twelve months or less from the balance sheet date are classified as short-term; otherwise, they are classified as long-term on the consolidated balance sheet.

The following table provides the Company’s marketable securities by security type as of June 30, 2015 and December 31, 2014 (in thousands):

	As of June 30, 2015
	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Commercial paper and corporate bonds	$	415,067	$	30	$	(546	)	$	414,551
U.S. government agency debt securities	14,501		7		(8		)	14,500
Total	$	429,568	$	37	$	(554	)	$	429,051

	As of December 31, 2014
	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Commercial paper and corporate bonds	$	417,845	$	72	$	(791	)	$	417,126
Total	$	417,845	$	72	$	(791	)	$	417,126

Contractual maturities of the Company’s marketable securities as of June 30, 2015 and December 31, 2014 are summarized as follows (in thousands):

	As of June 30, 2015				As of December 31, 2014
	Cost		Estimated Fair Value		Cost		Estimated Fair Value
Due in one year or less	$	222,701	$	222,625	$	233,326	$	233,284
Due in one to five years	206,867		206,426		184,519		183,842
Total	$	429,568	$	429,051	$	417,845	$	417,126

At June 30, 2015, the Company had $0.5 million of gross unrealized losses primarily due to a decrease in the fair value of certain corporate bonds. The Company regularly reviews its investment portfolio to identify and evaluate investments that have indications of possible impairment. Investments that are impaired are those that are considered to have losses that are other-than-temporary. Factors considered in determining whether a loss is temporary include:

• the length of time and extent to which fair value has been lower than the cost basis;

•the financial condition, credit quality and near-term prospects of the investee; and

•whether it is more likely than not that the Company will be required to sell the security prior to recovery.

As the Company has the ability and intent to hold these investments until a recovery of fair value, which may be until maturity, the Company has determined that the gross unrealized losses on such investments at June 30, 2015 are temporary in nature. Accordingly, the Company did not consider its investments in marketable securities to be other-than-temporarily impaired as of June 30, 2015.

The following tables provide the fair market value and the gross unrealized losses of the Company's marketable securities with unrealized losses, aggregated by security type, as of June 30, 2015 and December 31, 2014 (in thousands):

	In Loss Position for Less than 12 Months
	As of June 30, 2015					As of December 31, 2014
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Commercial paper and corporate bonds	$	283,863	$	(501	)	$	322,938	$	(791	)
U.S. government agency debt securities	14,500		(8		)	—		—
Total	$	298,363	$	(509	)	$	322,938	$	(791	)

	In Loss Position for More than 12 Months
	As of June 30, 2015					As of December 31, 2014
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Commercial paper and corporate bonds	$	32,834	$	(45	)	$	—	$	—
Total	$	32,834	$	(45	)	$	—	$	—

During the three and six months endedJune 30, 2015 and 2014, the Company recorded an insignificant amount of net realized gains from the sale of marketable securities.