Cash Equivalents and Investments (Tables)

6 Months Ended

Jun. 30, 2013

Cash and Cash Equivalents [Abstract]

Summary of cash and available-for-sale securities

Summary of Cash and Available-For-Sale Securities	Adjusted Cost		Unrealized Gains		Unrealized Losses		Estimated Fair Value		Cash and Cash Equivalents		Restricted Investment		Short-Term Marketable Securities
(In thousands)
June 30, 2013
Cash	$	11,217	$	—	$	—	$	11,217	$	11,217	$	—	$	—
Money market funds	240,256		—		—		240,256		240,256		—		—
Certificates of deposit	26,375		—		—		26,375		—		$	20,000	6,375
Corporate debt securities	1,001		1		—		1,002		—		—		1,002
Total	$	278,849	$	1	$	—	$	278,850	$	251,473	$	20,000	$	7,377
December 31, 2012
Cash	$	7,894	$	—	$	—	$	7,894	$	7,894	$	—	$	—
Money market funds	121,095		—		—		121,095		121,095		—		—
Certificates of deposit	26,128		—		—		26,128		2,223		20,000		3,905
Corporate debt securities	13,562		10		—		13,572		—		—		13,572
Total	$	168,679	$	10	$	—	$	168,689	$	131,212	20,000		$	17,477

Cash and available-for-sale securities classified by contractual maturity date

Cash and Available-For-Sale Securities by Contractual Maturity	June 30, 2013				December 31, 2012
(In thousands)	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Less than one year	$	278,849	$	278,850	$	168,679	$	168,689
Greater than one year but less than five years	—		—		—		—
Total	$	278,849	$	278,850	$	168,679	$	168,689