Cash and Cash Equivalents and Short-term Investments (Tables)

3 Months Ended

Mar. 31, 2014

Cash and Cash Equivalents and Short-term Investments

Certain information related to our cash and cash equivalents and short term investments

	March 31, 2014							December 31, 2013
	Fair Value		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Fair Value		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses
	(In thousands)
Cash and cash equivalents	$	326,881	$	—	$	—		$	389,915	$	—	$	—
Short-term investments:
Available-for-sale equity securities	77,591		49,045		—			96,942		68,395		—
Available-for-sale debt securities:
Corporate debt securities	19,525		4,252		—			19,388		4,122		—
Mortgage-backed debt securities	209		11		—			210		11		—
Mortgage-CMO debt securities	20		—		(1		)	20		—		(2		)
Asset-backed debt securities	541		1		(37		)	658		2		(54		)
Total available-for-sale debt securities	20,295		4,264		(38		)	20,276		4,135		(56		)
Total available-for-sale securities	97,886		53,309		(38		)	117,218		72,530		(56		)
Total short-term investments	97,886		53,309		(38		)	117,218		72,530		(56		)
Total cash, cash equivalents and short-term investments	$	424,767	$	53,309	$	(38	)	$	507,133	$	72,530	$	(56	)

Gross unrealized losses of cash and cash equivalents and short-term investments

	As of March 31, 2014
	Less Than 12 Months				More Than 12 Months
	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
	(In thousands)
Available-for-sale debt securities: (1)
Mortgage-CMO debt securities	$	20	$	1	$	—	$	—
Asset-backed debt securities	—		—		361		37
Total available-for-sale debt securities	20		1		361		37
Total	$	20	$	1	$	361	$	37

(1) Our unrealized losses on available-for-sale debt securities held for more than one year are comprised of various types of securities.  Each of these securities has a rating ranging from “A” to “AAA” from Standard & Poor’s and ranging from “A2” to “Aaa” from Moody’s Investors Service and is considered to be of high credit quality.  In each case, we do not intend to sell these investments, and it is less likely than not that we will be required to sell them to satisfy our own cash flow and working capital requirements.  We believe that we will be able to collect all amounts due according to the contractual terms of each investment and, therefore, do not consider the decline in value of these investments to be other-than-temporary at March 31, 2014.

Estimated fair values of corporate, mortgage-backed, mortgage-CMO and asset-backed debt securities

	Estimated
	Fair Value
	March 31, 2014
	(In thousands)
Debt securities:
Due in one year or less	$	—
Due after one year through five years	15,525
Due in more than five years	4,770
Total debt securities	$	20,295

Debt and equity securities

	Three Months Ended March 31,
	2014		2013
	(In thousands)
Available-for-sale
Proceeds from sales and maturities	$	135	$	86,601
Realized gains (losses), net	$	—	$	75,974