Study of Safety and Efficacy of BCL201 and Idelalisib in Patients With FL and MCL

Inclusion Criteria: * Histologically confirmed diagnosis of FL or MCL according to WHO 2008 * Relapsed or refractory with at least one (FL) or two (MCL), but not more than four, prior lines of antineoplastic regimens. * Either FDG-avid on FDG-PET or measurable disease by CT on cross sectional imaging: \> 1.5 cm for nodal lesion, \> 1.0 cm for extra nodal lesion. * Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 2 Exclusion Criteria: * For dose escalation part: Patients with MCL at high risk for tumor lysis syndrome * Prior treatment with PI3Kδ or Bcl-2 inhibitors. * Any other malignant disease * History of serious allergic reactions including anaphylaxis and toxic epidermal necrolysis * Inadequate organ function * Concomitant treatment with: * Strong CYP3A4/5 inducers or inhibitors * Sensitive CYP3A4/5 substrates or CYP3A4/5 substrates with narrow therapeutic index (NTI) * Sensitive CYP2D6 substrates or CYP2D6 substrates with NTI * Selected dual substrates of CYP3A4/5 and CYP2C8 * Selected dual substrates of CYP3A4/5 and CYP2D6 * Selected dual substrates of OATP and CYP450 * Selected dual substrates of CYP3A4/5 and P-gp * NTI P-gp substrates * QT prolonging drugs with a known risk to induce TdP * Proton pump inhibitors * Treatment by warfarin or equivalent vitamin K antagonists. * Other investigational therapies * Herbal preparations/ medications * Grapefruit, Seville oranges or products containing either juice Other protocol-defined inclusion/exclusion may apply.