Investments

3 Months Ended

Mar. 31, 2012

Investments [Abstract]

Investments

7. Investments

Our available-for-sale investments were classified as short-term investments on our March 31, 2012, December 31, 2011 and March 31, 2011 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:
	March 31, 2012							December 31, 2011							March 31, 2011
	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 (Losses)
Available- for-Sale Investments:
Government obligations	$	80,445	$	80,446	($	1	)	$	100,517	$	100,480	$	37		$	100,658	$	100,691	($	33	)
Government agency obligations		17,022		17,022		0			31,351		31,354		(3	)		33,172		33,187		(15	)
Corporate obligations		17,339		17,340		(1	)		16,620		16,633		(13	)		13,437		13,441		(4	)
	$	114,806	$	114,808	($	2	)	$	148,488	$	148,467	$	21		$	147,267	$	147,319	($	52	)

We also held a certificate of deposit with a total principal value of $5,345 as of March 31, 2011. This investment was included in Short-term investments on our Condensed Consolidated Balance Sheet as of March 31, 2011. We did not hold a certificate of deposit as of March 31, 2012 or December 31, 2011. We had $114,806 of debt securities classified as available-for-sale as of March 31, 2012, 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 March 31,
	2012			2011
Unrealized gains	$	0		$	0
Unrealized losses	($	23	)	($	133	)

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 March 31,
	2012		2011
Interest income on investments	$	141	$	155
Realized net gains on the sale of investments		14		145
	$	155	$	300