Marketable Securities

12 Months Ended

Dec. 31, 2014

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

6. Marketable Securities

We report our investments in marketable securities as current assets in our Consolidated Balance Sheets in “Marketable securities,” representing the investment of cash available for current operations. See Note 8.

Our investments in marketable securities are classified as available for sale and are summarized as follows:

	December 31, 2014
	Amortized Cost		Unrealized Gain (Loss)			Market Value
	(In thousands)
Corporate bonds	$	16,003	$	(104	)	$	15,899
Mortgage-backed securities		130		4			134
Total	$	16,133	$	(100	)	$	16,033

	December 31, 2013
	Amortized Cost		Unrealized Gain (Loss)			Market Value
	(In thousands)
U.S. Treasury Bills and Notes (due within one year)	$	1,749,879	$	(22	)	$	1,749,857
Mortgage-backed securities		188		8			196
Total	$	1,750,067	$	(14	)	$	1,750,053

Proceeds from maturities and sales of marketable securities and gross realized gains and losses are summarized as follows:

	Year Ended December 31,
	2014			2013			2012
	(In thousands)
Proceeds from maturities	$	8,000,000		$	4,650,000		$	2,575,000
Proceeds from sales		57			85			150,118
Gross realized gains		—			—			—
Gross realized losses		(1	)		(1	)		(6	)

As of December 31, 2014, the majority of our marketable securities had matured. Our level of investment activity is dependent on our working capital and other capital requirements during the year, as well as a response to actual or anticipated events or conditions in the securities markets.