Bind ng-grid on dropdown selected index change using angularjs

$scope.GetUserDetailsByCompany = function (item) {
    var params = { companyId: item.CompanyID };
    $http.get("UserCriteria/GetUserDetailsByCompany", { params: params }).success(function (data) {
        $scope.userData = data.UsersData;
        $scope.gridOptions = { data: 'userData' };
    });
}

<select ng-model="ddlCompany" class="form-control" ng-options="c.CompanyName for c in CompanyData track by c.CompanyID" ng-change="GetUserDetailsByCompany(ddlCompany)">                       
 
<div class="gridStyle" ng-grid="gridOptions">            
</div>