Inclusion Criteria:  Histologically confirmed diagnosis of B-cell NHL such as DLBCL, FL and MCL Patients received at least 2 lines of systemic therapy Previously received anti- CD20 treatment Patients in stage II should also be unsuitable or unwilling to receive allogeneic hematopoietic stem cell transplantation Patients must have an acceptable organ function  Exclusion Criteria:  Previously treated with PI3K inhibitors or BTK inhibitors Unresolved toxicity of CTCAE grade > 1 from prior anti-lymphoma therapy Chemotherapy or other investigational therapy within 28 days (or 5 times the half-life time, whichever is shorter) before starting cycle 1 Significant concurrent medical disease or condition which according to the investigators' judgement Active hepatitis B, C or HIV infection Infection requiring treatment 2 weeks prior to the first dosing