Short-Term Investments And Fair Value Measurement (Tables)

6 Months Ended

Jun. 30, 2011

Short-Term Investments And Fair Value Measurement

Available-For-Sale Securities Reported At Fair Value

	June 30, 2011
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Cash	$	167,990	$	—	$	—		$	167,990
Level 1 securities (1):
Money market funds		11,779		—		—			11,779
Level 2 securities (3):
Corporate debt securities		110,910		909		(34	)		111,785
Government and agency securities		87,699		653		(1	)		88,351
Asset and mortgage-backed securities		1,007		57		—			1,064
	$	379,385	$	1,619	$	(35	)	$	380,969
Less: Long-term restricted cash (1)									(4,562	)
Total cash, cash equivalents and short-term investments								$	376,407

	December 31, 2010
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Cash	$	194,146	$	—	$	—		$	194,146
Level 1 securities (2):
Money market funds		4,914		—		—			4,914
Level 2 securities (3):
Corporate debt securities		109,745		1,043		(101	)		110,687
Government and agency securities		42,062		331		(101	)		42,292
Asset and mortgage-backed securities		2,881		168		(140	)		2,909
	$	353,748	$	1,542	$	(342	)		354,948
Less: Long-term restricted cash (2)									(4,561	)
Total cash, cash equivalents and short-term investments								$	350,387

(1) Includes $7.2 million that is included in cash and cash equivalents and $4.6 million of long-term restricted cash that is included in other non-current assets as these funds represent restricted cash related to workers compensation deposits.

(2) Includes $0.4 million that is included in cash and cash equivalents and $4.6 million of long-term restricted cash that is included in other non-current assets as these funds represent restricted cash related to workers compensation deposits.

(3) Included in short-term investments.

Estimated Fair Value Of Short-Term Investments By Contractual Maturity

	(in thousands)
Due within one year	$	72,158
Due after one year and through 5 years		127,978
Due after 5 years and through 10 years		—
Due after 10 years		1,064
Total short-term investments	$	201,200