Cash and Investments in Marketable Securities (Tables)

12 Months Ended

Dec. 31, 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
	December 31, 2013		December 31, 2012
Cash and cash equivalents	$	39,067	$	25,437
Short-term investments		197,959		251,757
Restricted cash		25,000		25,000
Total cash and investments in marketable securities	$	262,026	$	302,194

Portfolio of Cash and Investments in Marketable Securities

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

	Fair  Value Hierarchy Level		Estimated Fair Value at
			December 31, 2013		December 31, 2012
Corporate notes and bonds		2	$	138,515	$	241,158
U.S. corporate commercial paper		2		59,444		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				197,959		252,760
Money market funds		1		26,453		22,487
Cash, including restricted cash		N/A		37,614		26,947
Total cash and investments in marketable securities			$	262,026	$	302,194