Financial Instruments

6 Months Ended

Jun. 30, 2015

Investments, Debt and Equity Securities [Abstract]

Financial Instruments

FINANCIAL INSTRUMENTS

The following is a summary of marketable securities at June 30, 2015 and December 31, 2014 (in thousands):

	June 30, 2015
	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Values
Available-for-sale securities
Corporate bonds and notes	$	311,108	$	81	$	(513	)	$	310,676
Municipal bonds and notes	73,590		13		(96		)	73,507
Commercial paper	9,389		3		—			9,392
Treasury and agency notes and bills	19,202		10		(6		)	19,206
Money market funds	2,296		—		—			2,296
Total available-for-sale securities	$	415,585	$	107	$	(615	)	$	415,077
Reported in:
Cash and cash equivalents								$	4,596
Short-term investments								410,481
Total marketable securities								$	415,077

	December 31, 2014
	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Values
Available-for-sale securities
Corporate bonds and notes	$	282,279	$	13	$	(538	)	$	281,754
Municipal bonds and notes	37,201		15		(1		)	37,215
Treasury and agency notes and bills	41,271		10		(13		)	41,268
Commercial paper	33,774		2		(1		)	33,775
Money market funds	20,883		—		—			20,883
Total available-for-sale securities	$	415,408	$	40	$	(553	)	$	414,895
Reported in:
Cash and cash equivalents								$	31,382
Short-term investments								383,513
Total marketable securities								$	414,895

At June 30, 2015 and December 31, 2014, the Company had $431.9 million and $434.4 million, respectively, in cash, cash equivalents and short-term investments. The majority of these amounts were held in marketable securities, as shown above. The remaining balance of $16.8 million and $19.5 million at June 30, 2015 and December 31, 2014, respectively, was cash held in operating accounts not included in the tables above.

The gross realized gains and losses on sales of marketable securities were not significant during the three and six months ended June 30, 2015 and 2014.

Unrealized losses and unrealized gains were $0.4 million and $0.1 million, respectively, net of tax, as of June 30, 2015. These amounts were related to temporary fluctuations in value of the remaining available-for-sale securities and were due primarily to changes in interest rates and market and credit conditions of the underlying securities. Certain investments with a temporary decline in value are not considered to be other-than-temporarily impaired as of June 30, 2015 because the Company has the ability to hold these investments to allow for recovery, does not anticipate having to sell these securities with unrealized losses and continues to receive interest at the maximum contractual rate. For the three months ended June 30, 2015 and 2014, respectively, the Company did not record any impairment charges related to its marketable securities.

The following table summarizes the fair value and gross unrealized losses related to individual available-for-sale securities at June 30, 2015 and December 31, 2014, which have been in a continuous unrealized loss position, aggregated by investment category and length of time (in thousands):

June 30, 2015	Less Than 12 Months					12 Months or More					Total
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Corporate bonds and notes	$	190,667	$	(475	)	$	46,714	$	(38	)	$	237,381	$	(513	)
Treasury and agency notes and bills	4,618		(6		)	—		—			4,618		(6		)
Municipal bonds and notes	56,584		(96		)	—		—			56,584		(96		)
Total	$	251,869	$	(577	)	$	46,714	$	(38	)	$	298,583	$	(615	)

December 31, 2014	Less Than 12 Months					12 Months or More					Total
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Corporate bonds and notes	$	240,165	$	(535	)	$	5,453	$	(3	)	$	245,618	$	(538	)
Municipal bonds and notes	1,061		(1		)	—		—			1,061		(1		)
Commercial paper	9,482		(1		)	—		—			9,482		(1		)
Treasury and agency notes and bills	16,245		(13		)	—		—			16,245		(13		)
Total	$	266,953	$	(550	)	$	5,453	$	(3	)	$	272,406	$	(553	)

The estimated fair value of marketable securities by contractual maturity at June 30, 2015 is shown below (in thousands). Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations without call or prepayment penalties.

	Estimated Fair Value
Due in one year or less	$	142,238
Due in one to two years	144,683
Due in two to three years	128,156
Total	$	415,077