Fair Value of Financial Instruments. For certain of the Company’s financial instruments, including cash held in banks, accounts receivable and accounts payable, the carrying amounts approximate fair value due to their short maturities, and are therefore excluded from the fair value tables below.

The Company categorizes the fair value of its financial assets and liabilities according to the hierarchy established by the FASB, which prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy are:



Level 1	Valuations based on quoted prices in active markets for identical assets or liabilities that the Company has the ability to directly access.
Level 2	Valuations based on quoted prices for similar assets or liabilities; valuations for interest-bearing securities based on non-daily quoted prices in active markets; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable data for substantially the full term of the assets or liabilities.
Level 3	Valuations based on inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

In circumstances in which a quoted price in an active market for the identical liability is not available, the Company is required to use the quoted price of the identical liability when traded as an asset, quoted prices for similar liabilities, or quoted prices for similar liabilities when traded as assets. If these quoted prices are not available, the Company is required to use another valuation technique, such as an income approach or a market approach.

The Company’s financial assets are measured at fair value on a recurring basis. Instruments that are classified within Level 1 of the fair value hierarchy generally include money market funds, U.S. Treasury securities and equity securities. Level 1 securities represent quoted prices in active markets, and therefore do not require significant management judgment.

Instruments that are classified within Level 2 of the fair value hierarchy primarily include government agency securities, asset-backed securities, mortgage-backed securities, commercial paper, U.S. government-sponsored agency securities and corporate/municipal notes and bonds. The Company’s Level 2 securities are primarily valued using quoted market prices for similar instruments and nonbinding market prices that are corroborated by observable market data. The Company uses inputs such as actual trade data, benchmark yields, broker/dealer quotes and other similar data, which are obtained from independent pricing vendors, quoted market prices or other sources to determine the ultimate fair value of the Company’s assets and liabilities. The inputs and fair value are reviewed for reasonableness and may be further validated by comparison to publicly available information or compared to multiple independent valuation sources. In addition, the Company reviews third-party valuation models, independently calculates the fair value of selective financial instruments and assesses the controls at its third-party valuation service providers in determining the overall reasonableness of the fair value of its Level 2 financial instruments.