Study of the Bruton's Tyrosine Kinase Inhibitor in Subjects With Relapsed/Refractory Marginal Zone Lymphoma

* Histologically documented marginal zone lymphoma including splenic, nodal, and extranodal sub-types; subjects with splenic MZL must have an additional measurable lesion, nodal or extranodal, as described in inclusion criteria 5 * Previously received one or more lines of therapy including at least one CD20-directed regimen (either as monotherapy or as chemoimmunotherapy) with documented failure to achieve at least PR or documented PD after, the most recent systemic treatment regimen * Men and women ≥18 years of age * ECOG performance status of ≤2 * ≥1 measurable lesion site on CT scan (\>1.5 cm in longest dimension). Lesions in anatomical locations (such as extremities or soft tissue lesions) that are not well visualized by CT may be measured by MRI instead. (Subjects with spleen-only disease are considered as not having measurable disease.) * Life expectancy of \>3 months, in the opinion of the investigator

* Medically apparent CNS lymphoma or leptomeningeal disease * History of other malignancies except adequately treated non melanoma skin cancer, curatively treated in-situ cancer, or other solid tumors curatively treated with no evidence of disease for ≥2 years * History of allogeneic stem-cell (or other organ) transplantation * Any chemotherapy, anticancer antibodies, or other systemic anticancer therapy within 21 days of the first dose of study drug * Any external beam radiation therapy within 6 weeks prior to the first dose of the study drug * Concurrent use of warfarin or other vitamin K antagonists * Concurrent use of a strong CYP3A inhibitor. Subjects who have received a strong CYP3A inhibitor prior to entering the study must have discontinued therapy for at least 5 half lives of the prohibited medication. * Recent infection requiring IV anti-infective treatment that was completed ≤14 days before the first dose of study drug * Unresolved toxicities from prior anti-cancer therapy, defined as having not resolved to CTCAE Grade 0 or 1, or to the levels dictated in the eligibility criteria with the exception of alopecia * Inadequate organ function as defined on laboratory tests