navidea biopharmaceuticals, inc., a biopharmaceutical company, focuses on the development and commercialization of precision immunodiagnostic agents and immunotherapeutics. it operates through two segments, diagnostic substances and therapeutic development programs. the company develops manocept platform to target the cd206 mannose receptor expressed on activated macrophages. its cd206-targeted drug platform is applicable to a range of diagnostic modalities, including single photon emission computed tomography, positron emission tomography (pet), imaging and topical gamma-scanning, and intra-operative and/or optical-fluorescence detection, as well as delivery of therapeutic compounds that target macrophages, and immune-and inflammation-involved diseases. further, the company offers nav4694, a fluorine-18 labeled pet imaging agent for use as an aid in the imaging and evaluation of patients with signs or symptoms of alzheimer's disease and mild cognitive impairment. in addition, it is de