Inclusion Criteria:

          -  Non-child bearing potential or able to follow birth control requirements

          -  Eastern Cooperative Oncology Group (ECOG) ≤ 1

          -  Life expectancy ≥ 12 weeks

          -  Laboratory criteria as:

               -  Neutrophil count ≥ 1,500/mm3

               -  Platelet count ≥ 7.5 x 104 /mm3

               -  Hemoglobin ≥ 9.0 g/dL

               -  Lymphocyte count ≥ 500/mm3

               -  Serum creatinine < 1.5 x institutional Upper Limit of Normal (ULN) or an
                  estimated glomerular filtration rate (eGFR) of > 50 ml/min as calculated by the
                  Modification of Diet in Renal Disease (MDRD) equation

               -  Total bilirubin < 1.5 x ULN (except for subjects with documented Gilbert's
                  syndrome)

               -  Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) < 3.0 x ULN

          -  Dose escalation subjects: Epidermal Growth Factor Receptor (EGFR) activating mutation
             by local testing: exon 18 G719X, exon 19 deletion, exon 21 L861Q, exon 21 L858R or
             exon 20 insertion; and received prior treatment with EGFR Tyrosine Kinase Inhibitor
             (TKI)

          -  Response expansion/RP2D expansion/ FE Cohort subjects: disease progression on or was
             intolerant to prior EGFR TKI; activating mutation as above AND T790M mutation; tumor
             sample subsequent to EGFR TKI is available for central testing; at least one
             measurable lesion per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1

        Inclusion Criteria for Exon 20 cohort:

          -  Subject on any line of treatment and has an EGFR exon 20 insertion mutation on
             examination of an NSCLC tissue or cellular specimen. Local testing may determine
             eligibility and a tumor sample should also be sent for central testing.

          -  Subjects must have at least 1 measurable lesion based on RECIST version 1.1.

        Exclusion Criteria:

          -  Any ongoing toxicity ≥ Grade 2 attributable to prior Non-Small-Cell Lung Cancer
             (NSCLC) treatment

          -  Prior EGFR inhibitor within 6 days; received prior treatment with any other agent with
             antitumor activity chemotherapy, radiotherapy, or immunotherapy within 14 days; any
             investigational therapy within 28 days or 5 half-lives, whichever is shorter; blood
             transfusion or hemopoietic factor within 14 days; major surgery within 14 days; any
             strong CYP3A4 inhibitors within 7 days

          -  Positive hepatitis B surface antigen (HBsAg) or hepatitis C antibody (anti-HCV) or
             Human Immunodeficiency Virus (HIV)

          -  Symptomatic Central Nervous System (CNS) metastasis

          -  Active infection requiring systemic therapy within 14 days

          -  Severe or uncontrolled systemic diseases including uncontrolled hypertension

          -  History of or active interstitial lung disease

          -  Screening QTcF >450 msec or current medication known to prolong QT

          -  ≥ Grade 2 cardiac arrhythmia or uncontrolled atrial fib of any grade; Class 3 or 4 New
             York Heart Association congestive heart failure; history of severe/unstable angina,
             myocardial infarction or cerebrovascular accident within 6 months

          -  History of gastrointestinal ulcer or bleeding within 3 months; any digestive tract
             dysfunction

          -  Concurrent corneal disorder or ophthalmologic condition making subject unsuitable

          -  RP2D cohort subjects: contraindications to midazolam, any other midazolam within 7
             days, or any medications or supplements known to be strong CYP3A inhibitors within 7
             days or inducers within 12 days

          -  Any other malignancy requiring treatment