We invest our excess cash in high-quality U.S. Government, government-backed (e.g., Fannie Mae, FDIC guaranteed bonds and certificates of deposit) and corporate debt instruments, which bear lower levels of relative risk. We believe that the effect, if any, of reasonably possible near-term changes in interest rates on our financial position, results of operations and cash flows should not be material to our cash flows or income. It is possible that interest rate movements would increase our unrealized gain or loss on debt securities. We do not currently hedge our foreign currency exchange rate risk. We estimate that any market risk associated with our international operations or investments is unlikely to have a material adverse effect on our business, financial condition or results of operation. Our portfolio of marketable securities is subject to interest rate risk and the credit rating of our investments may be affected by the underlying financial health of the guarantors of our investments. We use silicon wafers but do not enter into forward or futures hedging contracts to mitigate against risks related to the price of silicon. Item