private function addTermData($termData)
    {
        $labelsByThesaurusId = [];

        foreach ($termData as $currentTerm) {
            $label = $currentTerm['expansions_terms'];

            if (isset($currentTerm['expanded_term']) && $currentTerm['expanded_term']) {
                $label = sprintf("%s => %s", $currentTerm['expanded_term'], $label);
            }

            $labelsByThesaurusId[$currentTerm['thesaurus_id']][] = $label;
        }

        foreach ($labelsByThesaurusId as $thesaurusId => $labels) {
            $this->_items[$thesaurusId]->setData('terms_summary', implode(" <br/> ", $labels));
        }

        return $this;
    }