. up to 400000 shares of common stock may be awarded under the directors 2019 plan . options outstanding under the director 2019s plan have vesting periods of 1 to 5 years from the date of grant and options expire ten years from the date of grant grant-date fair value the company estimates the fair value of each stock option granted at the grant date using the black-scholes option valuation model , consistent with the provisions of sfas no . 123 ( r ) , sec sab no