Inclusion Criteria:

          -  Has hematocytological or pathological diagnosis of non- Hodgkin's lymphoma (NHL)

          -  Has relapsed from or is refractory to standard treatment or no standard treatment is
             available

          -  Is the age of majority in their country (18 in the US and 20 in Japan) at the time of
             informed consent

          -  Has Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1

          -  Has at least one evaluable lesion site (not applicable for the DDI cohort)

          -  Has preserved organ function based on baseline laboratory data at screening tests

          -  If of reproductive potential, agrees to avoid harvesting ova or sperm, and to use a
             protocol-defined form of contraception or avoid intercourse, during and upon
             completion of the study, and for at least 3 months after the last dose of study drug

          -  Tumor biopsy collections:

               1. willing to provide archived or fresh tumor tissue samples that are sufficient for
                  comprehensive genomic and/or proteomic analyses at baseline

               2. [US only] willing to provide fresh on-treatment tumor biopsy if deemed acceptable
                  risk by the investigator

                  [Japan only] fresh on-treatment tumor biopsy should be performed if deemed
                  acceptable risk by the investigator

               3. willing to provide optional fresh end-of-treatment biopsy

        For ATL subjects:

          -  Has a positive test result for human T-lymphotropic virus type I antibody

          -  Has ATL subtype classified as acute, lymphomatous, or chronic with poor prognostic
             factor

          -  Has diagnosis of relapse (including relapse after partial remission [PR]) or
             treatment-resistant ATL at the time of informed consent after prior treatment with at
             least 1 anti-cancer medication regimen

        Exclusion Criteria:

          -  Has been diagnosed with protocol-defined cutaneous T-cell lymphoma or T-cell leukemia.
             For DDI cohort, CTCL is not exclusionary.

          -  Has a history or presence of central nervous system (CNS) involvement

          -  Has a medical history, complication or other malignancy considered inappropriate for
             participation in the study, or a serious physical or psychiatric disease, the risk of
             which may be increased by participation in the study

          -  Has received drugs or other treatments not allowed by the protocol

          -  History of treatment with other enhancer of zeste (EZH) inhibitors

          -  Has had allogeneic hematopoietic stem cell transplantation (HTCP) within 90 days
             before scheduled dosing on Cycle 1 Day 1

          -  Is pregnant or breastfeeding

          -  Is otherwise deemed ineligible to participate by the investigator or sub-investigator

        DDI Cohort Only:

          -  Has received following medications within 14 days prior to study drug administration

          -  Any CYP3A inhibitors/inducers including weak CYP3A inhibitors/inducers, and P-gp
             inhibitors, midazolam as well as digoxin