Investments

6 Months Ended

Jun. 30, 2011

Investments

Investments

7. Investments

Our available-for-sale investments were classified as short-term investments on our June 30, 2011, December 31, 2010 and June 30, 2010 Condensed Consolidated Balance Sheets. The following table sets forth the aggregate fair value, amortized cost basis and the net unrealized gains and losses included in accumulated other comprehensive income (loss) of our available-for-sale investments as of the dates indicated:

	As of:
	June 30, 2011						December 31, 2010						June 30, 2010
	Aggregate Fair Value		Amortized Cost		Net Unrealized Gains (Losses)		Aggregate Fair Value		Amortized Cost		Net Unrealized Gains (Losses)		Aggregate Fair Value		Amortized Cost		Net Unrealized Gains
Available- for-Sale Investments:
Government obligations		$100,679		$100,664		$15		$110,560		$110,550		$10		$90,440		$90,416		$24
Government agency obligations		26,235		26,237		(2)		24,394		24,399		(5)		31,644		31,628		16
Corporate obligations		20,222		20,241		(19)		8,903		8,908		(5)		12,182		12,175		7
		$147,136		$147,142		($6)		$143,857		$143,857		$0		$134,266		$134,219		$47

We also held a certificate of deposit with a total principal value of $5,303 as of December 31, 2010 and $5,220 as of June 30, 2010. We did not hold a certificate of deposit as of June 30, 2011. This investment was included in Short-term investments on our Condensed Consolidated Balance Sheets as of the applicable dates. We had $147,136 of debt securities classified as available-for-sale as of June 30, 2011, and all of those debt securities had contractual maturities within one year.

The following table sets forth the unrealized gains and losses on available-for-sale investments that were included in other comprehensive income (loss) in the periods indicated:

	Three Months Ended June 30,				Six Months Ended June 30,
	2011		2010		2011			2010
Unrealized gains		$46		$62		$0			$70
Unrealized losses		$0		$0		($87	)		$0

The following table sets forth the components of investment income included in Interest income in our Condensed Consolidated Statements of Income in the periods indicated:

	Three Months Ended June 30,				Six Months Ended June 30,
	2011		2010		2011		2010
Interest income on investments		$116		$213		$271		$366
Realized net gains on the sale of investments		51		6		196		99
		$167		$219		$467		$465