FAIR VALUE MEASUREMENTS

6 Months Ended

Jun. 30, 2011

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS

NOTE 4. FAIR VALUE MEASUREMENTS

        Fair value is defined as the exchange price that would be received to sell an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The following three levels of inputs may be used to measure fair value under the fair value hierarchy:

• •

  Level 1—Quoted prices in active markets for identical assets or liabilities that can be accessed at the measurement date.

  •

  Level 2—Observable inputs other than quoted prices included within Level 1, such as quoted prices for similar assets or liabilities in active markets 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.

        If the inputs used to measure the financial assets and liabilities fall within more than one of the different levels described above, the categorization is based on the lowest level input that is significant to the fair value measurement of the instrument.

        As of June 30, 2011, we held $125,796,000 of cash equivalents and marketable securities consisting of equity securities, high quality marketable debt instruments of the U.S. government and U.S. government agencies, commercial paper, and a money market fund. We have adopted an investment policy and established guidelines relating to credit quality, diversification and maturities of our investments to preserve principal and maintain liquidity. All investment securities are issued by or guaranteed by the U.S. government and its federal agencies or have a credit rating of at least long-term of A or short-term of A1/P1 as determined by Moody's Investors Service and/or Standard & Poor's. We do not have any direct investments in auction-rate securities or securities that are collateralized by assets that include mortgages or subprime debt.

        The fair value measurements of our cash equivalents and available-for-sale marketable securities are identified at the following levels within the fair value hierarchy (in thousands):

	Fair Value Measurements Using
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
At June 30, 2011
Money market funds	$	—	$	21,202		—	$	21,202
Commercial paper		—		9,764		—		9,764
U.S. government and U.S government agency notes		—		91,365		—		91,365
Equity securities		3,465		—		—		3,465
	$	3,465	$	122,331		—	$	125,796
At December 31, 2010
Money market funds	$	—	$	1,044		—	$	1,044
Commercial paper		—		35,413		—		35,413
U.S. government and U.S. government agency notes		—		77,157		—		77,157
Equity securities		5,124		—		—		5,124
	$	5,124	$	113,614		—	$	118,738