This excerpt taken from the SIRF DEF 14A filed Mar 26, 2008.
Narrative to Summary Compensation Table and Grant of 2007 Plan-Based Awards
See our Compensation Discussion and Analysis above for complete description of compensation plans pursuant to which the amounts listed under the 2007 Summary Compensation Table and Grants of 2007 Plan-Based Awards were paid or awarded and the criteria for such payment, including targets for payment of annual incentives, as well as performance criteria on which such payments were based. The Compensation Discussion and Analysis also describes the options and restricted stock grants and performance awards.
Except as otherwise noted, all stock options vest over four years beginning on the grant date, with the first vesting occurring on the first anniversary of the grant date.