Financial Instruments	12 Months Ended
Dec. 31, 2017
Financial Instruments [Abstract]
Financial Instruments	18. Financial Instruments The Company does not hold or issue financial instruments for trading or hedging purposes, nor does it hold interest rate, leveraged, or other types of derivative financial instruments. Fair values of accounts receivable, accounts payable, accrued expenses and income taxes payable reflected in the December 31, 2017 and 2016 balance sheets approximate carrying values at those dates.

The entire disclosure for financial instruments. This disclosure includes, but is not limited to, fair value measurements of short and long term marketable securities, international currencies forward contracts, and auction rate securities. Financial instruments may include hedging and non-hedging currency exchange instruments, derivatives, securitizations and securities available for sale at fair value. Also included are investment results, realized and unrealized gains and losses as well as impairments and risk management disclosures.

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