 - Phase 1b: Patients must have a histologically confirmed solid malignancy, lymphoma or multiple myeloma for which standard curative or palliative measures do not exist, are no longer effective, or for which the patient is not eligible or refuses; phase 1b cohort expansion: patients must have a histologically confirmed cluster of differentiation CD-20 positive B-cell non-Hodgkin lymphoma for which standard curative or palliative measures do not exist, are no longer effective, or for which the patient is not eligible or refuses; phase 2a: patients must have histologically or cytologically confirmed marginal zone B-cell lymphoma, small lymphocytic lymphoma, lymphoplasmacytic lymphoma or mantle cell lymphoma, and must have at least one measureable site of disease 