Inclusion Criteria:

- Subjects who have been diagnosed with indolent NHL that has progressed.

- Subjects must have exhibited no response or progression within 6 months after the
last dose of a chemotherapy induction regimen or RIT.

- Subjects must have rituximab-refractory disease.

- Measurable disease with a lymph node or tumor mass ≥1.5 cm in at least one dimension
by CT.

- Adequate renal and hepatic function.

Exclusion Criteria:

- Candidate for potentially curative therapies in the opinion of the investigator.

- Previous treatment with a PI3K inhibitor within 30 days of starting IPI-145 therapy.

- Prior history of allogeneic hematopoietic stem cell transplant (HSCT).

- Prior chemotherapy, cancer immunosuppressive therapy, or other investigational agents
within 3 weeks before first dose of study drug.

- Grade 3B FL and/or clinical evidence of transformation to a more aggressive subtype
of lymphoma.

- Symptomatic central nervous system (CNS) NHL.

- Ongoing systemic bacterial, fungal, or viral infections at the time of initiation of
study treatment.