public function getId($iId = null)
    {
        $oInput = Factory::service('Input');
        $iId    = (int) $iId ?: (int) $oInput->get('id');

        if (empty($iId)) {
            throw new ApiException('Invalid Customer ID', 404);
        }

        $oCustomerModel = Factory::model('Customer', 'nails/module-invoice');
        $oCustomer      = $oCustomerModel->getById($iId);

        if (empty($oCustomer)) {
            throw new ApiException('Invalid Customer ID', 404);
        }

        return Factory::factory('ApiResponse', 'nails/module-api')
                      ->setData($this->formatCustomer($oCustomer));
    }