Sales of a substantial number of shares of common stock into the public market, or the perception that these sales could occur, could have a material adverse effect on our stock price. As of December 31, 2006, approximately 4.8 shares of our common stock were issuable upon exercise of outstanding stock options by employees and non-employee directors and we had the ability to issue up to an additional 6.5 shares as restricted stock, restricted stock units, or stock options under our 2002 Stock Compensation Plan. Additionally, we may issue a significant number of additional shares, in