Investments

9 Months Ended

Sep. 30, 2011

Investments [Abstract]

Investments

2. Investments

Investments consist of the following (in thousands):

	September 30, 2011		December 31, 2010
Short-term investments:
U.S. agency securities	$	750	$	2,250
Municipal securities		355		450
Corporate commercial paper		2,250		2,749
Foreign government bonds		500		775
Corporate debt securities		3,797		5,105
Total short-term investments		7,652		11,329
Long-term investment—auction rate security ("ARS")		116		122
Total investments	$	7,768	$	11,451

We record our investments at fair value. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. A three-tier fair value hierarchy is established as a basis for considering such assumptions and for inputs used in the valuation methodologies in measuring fair value:

Level 1:	Quoted prices in active markets for identical assets or liabilities.
Level 2:	Directly or indirectly observable market-based inputs or unobservable inputs used in models or other valuation methodologies.
Level 3:	Unobservable inputs that are not corroborated by market data. The inputs require significant management judgment or estimation.

Our short-term investments consist entirely of marketable securities classified as available for sale, and were valued based on quoted market prices of similar instruments and other significant Level 2 inputs derived from, or corroborated by, observable market data.

Our long-term investment consists entirely of a single ARS issuance. Due to the lack of observable market quotes on our ARS, we recorded an other-than-temporary impairment against this ARS issuance in prior periods reducing the cost basis of the investment to $116,000.

We had $1,000 of unrealized losses on our short-term investments as of both September 30, 2010, and December 31, 2011.