Inclusion Criteria:

- Confirmed diagnosis of relapsed/refractory CLL/SLL who require treatment and have
failed at least one prior therapy.

- Patients must have available results of interphase cytogenetics CLL fluorescent in
situ hybridization (FISH) panel; the cytogenetic analysis must be done prior to
starting therapy but after any recent therapy

- Eastern Cooperative Oncology Group (ECOG) performance status =< 2

- Life expectancy greater than 2 months

- Bilirubin =< 1.5 X the institutional upper limit of normal unless due to Gilbert's
disease or disease related to Aspartate aminotransferase (AST) or alanine
aminotransferase (ALT) =< 2.5 X the institutional upper limit of normal unless
disease related

- Creatinine =< 1.5 X the institutional upper limit of normal unless disease related

- Absolute neutrophil count (ANC) >= 0.75 X 10^9/L

- Platelet count >= 30 X 10^9/L

- Agree to use contraception during the study and for 30 days after the last dose of
study drug if sexually active and able to bear children

- Ability to understand and the willingness to sign a written informed consent document

- Patients with uncontrolled or active infection requiring antibiotic therapy; patients
with controlled infections who are receiving extended antibiotics or prophylactic
therapy are not excluded

Exclusion Criteria:

- Patients who have had chemotherapy, radiotherapy or immunotherapy within 4 weeks
prior to the first dose of study drug (corticosteroids for disease-related symptoms
allowed but doses equivalent to > 20 mg prednisone orally per day require 1 week
washout before study drug administration or steroid dose must be equal to =< 20 mg
prednisone orally daily)

- Patients who have not recovered from adverse events of >= grade 3 toxicity due to
agents administered more than 4 weeks ago

- Receiving any other investigational agents

- Previously randomized to any PCI-32765 clinical trial

- Known secondary malignancy that limits survival to less than two years

- Patients with malabsorption syndrome, disease significantly affecting
gastrointestinal function, or resection of the stomach or small bowel or ulcerative
colitis, symptomatic inflammatory bowel disease, or partial or complete bowel
obstruction

- Patients requiring anti-coagulation with warfarin or heparin products including low
molecular weight heparin (LMWH)

- Patients requiring treatment with a strong cytochrome P450 3A4/5 (CYP3A4/5) and/or
cytochrome P450 2D6 (CYP2D6) inhibitor

- Patients with a life-threatening illness, medical condition or organ system
dysfunction which, in the investigator's opinion, could compromise the subject's
safety, interfere with the absorption or metabolism of PCI-32765 PO, or put the study
outcomes at undue risk

- Significant cardiovascular disease such as uncontrolled or symptomatic arrhythmias,
congestive heart failure, or myocardial infarction within 6 months of screening, or
any Class 3 or 4 cardiac disease as defined by the New York Heart Association
Functional Classification

- Active central nervous system (CNS) involvement by lymphoma

- Pregnant or women who are breastfeeding