Inclusion Criteria:  Continuous non-smoker who has not used nicotine-containing products for at least 3 months prior to the first dose. Body mass index (BMI) >= 18.0 and =< 32.0 kg/m^2 at screening. Medically healthy with no clinically significant medical history, physical examination, laboratory profiles, vital signs, or electrocardiograms (ECGs), as deemed by the principal investigator (PI). Liver function tests must be =< upper limit of normal range (ULN). Women must be of non-childbearing status and must have negative serum pregnancy test results. Men of reproductive potential to follow protocol defined contraception methods. Able to swallow multiple capsules.  Exclusion Criteria:  Participant is mentally or legally incapacitated or has significant emotional problems at the time of the screening visit or expected during the conduct of the study. History or presence of clinically significant medical or psychiatric condition or disease in the opinion of the PI. History of any illness that, in the opinion of the PI, might confound the results of the study or poses an additional risk to the participant by their participation in the study. Presence of any clinically significant, ongoing systemic bacterial, fungal, or viral infections in the opinion of the PI. History or presence of alcoholism or drug abuse within the past 2 years prior to screening. Women who are pregnant or lactating. Positive urine drug or alcohol results at screening or check-in. Positive urine cotinine at screening. Positive results at screening for human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg) or hepatitis C virus (HCV). Seated blood pressure is less than 90/40 mm Hg or greater than 140/90 mmHg at screening. Seated heart rate is lower than 40 beats per minute (bpm) or higher than 99 bpm at screening. Hemoglobin level below the lower limit of normal at screening. Have been on a diet incompatible with the on-study diet, in the opinion of the PI, within the 28 days prior to the first dose of study drug, and throughout the study. Unable to refrain from or anticipates the use of any protocol defined drugs. Donation of blood or significant blood loss within 56 days prior to the first dose of study drug. Plasma donation within 7 days prior to the first dose of study drug.  Part 1 Only:  History or presence of clinically significant hypersensitivity or idiosyncratic reaction to ACP-196, calcium carbonate, related compounds, or any inactive ingredients. History or presence of liver disease.  Part 2 Only:  History or presence of clinically significant hypersensitivity or idiosyncratic reaction to ACP-196, omeprazole, related compounds or any inactive ingredients. History or presence of liver disease; Clostridium difficile-associated diarrhea.  Part 3 Only:  History or presence of clinically significant hypersensitivity or idiosyncratic reaction to ACP-196, rifampin, related compounds, or any inactive ingredients. History or presence of liver disease; diabetes mellitus. Estimated creatinine clearance < 90 mL/min at screening.