1. A computer-implemented method comprising: receiving, from an input device, an input phrase defining an initial scope of a concept search; identifying, by a processing device, a plurality of concept terms related to the input phrase in view of an analysis of documents in a data set; determining, by the processing device, a relevance score for each of the plurality of concept terms; determining, by the processing device, a set of concept terms from the plurality of concept terms that have a relevance score that exceeds a threshold value; displaying the set of concept terms at a first section of a graphical user interface (GUI); displaying the input phrase at a second section of the GUI; receiving, from the input device, a selection of a concept term from the set of concept terms; displaying, in the second section of the GUI, a visual representation of a relationship between the selected concept term and the input phrase in response to the selection of the concept term; identifying, by the processing device, one or more of the documents related to the selection of the concept term and the input phrase; displaying, in a third section of the GUI, a count of the one or more documents related to the selection of the concept term and the input phrase; receiving, from the input device, a selection of an additional concept term from the set of concept terms; identifying, by the processing device, one or more of the documents related to the selected concept term, the input phrase, and the additional concept term; updating the visual representation to indicate a relationship between the selected concept term, the additional concept term, and the input phrase; and displaying the one or more documents to a user.