Adding whitespace between tags in tagcloud

Could someone please tell me exactly what I need to add to this code to create more whitespace between the tags in my tagcloud?

$defaults = array(
            'exclude'  => '',
            'format'   => 'list',
            'include'  => $displayed_gallery->get_term_ids_for_tags(),
            'largest'  => 36,
            'link'     => 'view',
            'number'   => 0, // 45,
            'order'    => 'ASC',
            'orderby'  => 'name',
            'smallest' => 14,
            'taxonomy' => 'ngg_tag',
            'unit'     => 'pt'
        );
        $args = wp_parse_args('', $defaults);