Cash and Cash Equivalents, Short-Term Investments and Restricted Investments (Tables)

3 Months Ended

Mar. 31, 2013

Cash and Cash Equivalents, Short-Term Investments and Restricted Investments

The following are summaries of cash and cash equivalents, short-term investments and restricted investments (in thousands):

	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
As of March 31, 2013:
Cash	$	1,943	$	—	$	—		$	1,943
Money market funds		9,612		—		—			9,612
U.S. treasury securities		4,000		—		—			4,000
U.S. government-sponsored agencies		4,397		1		—			4,398
Corporate debt securities		95,171		19		(17	)		95,173
Certificates of deposit		1,955		—		—			1,955
	$	117,078	$	20	$	(17	)	$	117,081
Reported as:
Cash and cash equivalents								$	21,011
Short-term investments									94,115
Restricted investments									1,955
								$	117,081
As of December 31, 2012:
Cash	$	915	$	—	$	—		$	915
Money market funds		20,897		—		—			20,897
U.S. government-sponsored agencies		11,329		1		—			11,330
Corporate debt securities		105,839		32		(11	)		105,860
Certificates of deposit		1,955		—		—			1,955
	$	140,935	$	33	$	(11	)	$	140,957
Reported as:
Cash and cash equivalents								$	36,134
Short-term investments									102,868
Restricted investments									1,955
								$	140,957

Available-For-Sale Investments Measured at Fair Value

The Company’s available-for-sale investments, which include cash equivalents and short-term investments, are measured at fair value on a recurring basis and are classified at the following fair value hierarchy (in thousands):

			Fair Value Measurements at Reporting Date Using
Description	Total As of March 31, 2013		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money market funds	$	9,612	$	9,612	$	—	$	—
U.S. treasury securities		4,000		—		4,000		—
U.S. government-sponsored agencies		4,398		—		4,398		—
Corporate debt securities		95,173		—		95,173		—
Total	$	113,183	$	9,612	$	103,571	$	—

			Fair Value Measurements at Reporting Date Using
Description	Total As of December, 2012		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Money market funds	$	20,897	$	20,897	$	—	$	—
U.S. government-sponsored agencies		11,330		—		11,330		—
Corporate debt securities		105,860		—		105,860		—
Total	$	138,087	$	20,897	$	117,190	$	—