Cash and Investments in Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2013

Fair Value Disclosures [Abstract]

Cash and Investments in Marketable Securities, Including Cash Equivalents and Restricted Cash

Cash and investments in marketable securities, including cash equivalents and restricted cash, are as follows (in thousands):

	Estimated Fair Value at
	September 30, 2013		December 31, 2012
Cash and cash equivalents	$	65,411	$	25,437
Short-term investments		118,139		251,757
Restricted cash		25,000		25,000
Total cash and investments in marketable securities	$	208,550	$	302,194

Portfolio of Cash and Investments in Marketable Securities

Our portfolio of cash and investments in marketable securities includes (in thousands):

		Estimated Fair Value at
	Fair Value Hierarchy Level	September 30, 2013		December 31, 2012
Corporate notes and bonds	2	$	93,902	$	241,158
U.S. corporate commercial paper	2		28,036		3,990
Obligations of U.S. government agencies	2		—		6,108
Obligations of U.S. states and municipalities	2		—		1,504
Available-for-sale investments			121,938		252,760
Money market funds	1		58,751		22,487
Cash, including restricted cash	N/A		27,861		26,947
Total cash and investments in marketable securities		$	208,550	$	302,194