Cash, Cash Equivalents, and Available-For-Sale Investments (Tables)

6 Months Ended

Jun. 30, 2011

Cash, Cash Equivalents, and Available-For-Sale Investments (Tables) [Abstract]

Cash, cash equivalents, and available-for-sale investments

	Estimated Fair Value at
	June 30,		December 31,
	2011		2010
Cash and cash equivalents	$	11,626	$	17,755
Short-term investments		351,280		298,177
Long-term investments		118,941		—
Total cash, cash equivalents, and available-for-sale investments	$	481,847	$	315,932

Portfolio of cash, cash equivalents, and available-for-sale investments

	Estimated Fair Value at
	June 30,		December 31,
	2011		2010
Corporate notes and bonds	$	360,536	$	190,527
U.S. corporate commercial paper		101,434		82,361
Obligations of U.S. government agencies		8,251		25,289
Cash and money market funds		11,626		17,755
Total cash, cash equivalents, and available-for-sale investments	$	481,847	$	315,932

Portfolio of available-for-sale investments

	Estimated Fair Value at
	June 30,		December 31,
	2011		2010
Less than one year	$	351,280	$	298,177
Greater than one year but less than two years		118,941		—
Total available-for-sale investments	$	470,221	$	298,177

Financial assets measured at fair value on a recurring basis

	Level 1		Level 2		Level 3		Total
As of June 30, 2011:
Money market funds	$	10,594	$	—	$	—	$	10,594
U.S. corporate commercial paper		—		101,434		—		101,434
Corporate notes and bonds		—		360,536		—		360,536
Obligations of U.S. government agencies		—		8,251		—		8,251
Cash equivalents and available-for-sale investments	$	10,594	$	470,221	$	—	$	480,815
Cash								1,032
Cash, cash equivalents, and available-for-sale investments							$	481,847
As of December 31, 2010:
Money market funds	$	16,028	$	—	$	—	$	16,028
U.S. corporate commercial paper		—		82,361		—		82,361
Corporate notes and bonds		—		190,527		—		190,527
Obligations of U.S. government agencies		—		25,289		—		25,289
Cash equivalents and available-for-sale investments	$	16,028	$	298,177	$	—	$	314,205
Cash								1,727
Cash, cash equivalents, and available-for-sale investments							$	315,932

Level 1 —	Quoted prices in active markets for identical assets or liabilities.
Level 2 —	Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.
Level 3 —	Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.