Short-Term Investments And Fair Value Measurement (Tables)

9 Months Ended

Sep. 30, 2011

Short-Term Investments And Fair Value Measurement [Abstract]

Available-For-Sale Securities Reported At Fair Value

	September 30, 2011
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Cash	$	157,229	$	—	$	—		$	157,229
Level 1 securities (1):
Money market funds		6,532		—		—			6,532
Level 2 securities (3):
Corporate debt securities		116,569		743		(171	)		117,141
Government and agency securities		87,663		740		—			88,403
Asset and mortgage-backed securities		970		59		—			1,029
	$	368,963	$	1,542	$	(171	)	$	370,334
Less: Long-term restricted cash (1)									(4,562	)
Total cash, cash equivalents and short-term investments								$	365,772

	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 $2.0 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 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 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	$	96,056
Due after one year and through 5 years		109,488
Due after 5 years and through 10 years		—
Due after 10 years		1,029
Total short-term investments	$	206,573