Study of Danicopan in Participants With Hepatic Impairment

Key Inclusion Criteria: * Body mass index range of 18.0 to 40.0 kilograms (kg)/square meter with a minimum body weight of 50 kg at Screening. * Females must be of non-childbearing potential. * Males must agree to abstinence or use a highly effective method of contraception. HI Participants: * Be sufficiently healthy for study participation. * Diagnosis of chronic (\>6 months) stable hepatic insufficiency. * A stable medication regimen. * In good general health at Screening and check-in, allowing for the concurrent illnesses associated with HI. * Evidence of cirrhosis due to hepatitis C virus (HCV), hepatitis B virus (HBV) infection, cryptogenic, alcohol abuse, or nonalcoholic steatohepatitis. * No evidence of hepatocellular carcinoma. * Have HI as assessed by a Child-Pugh classification score at Screening. Healthy Participants: * Participants must be demographically matched to a hepatically impaired participant. * Medically healthy and without a clinically significant medical history. Key Exclusion Criteria: * Evidence of any other clinically significant deviation from normal in a clinical laboratory for the match-controlled participants and laboratory findings beyond those that are consistent with the degree of HI from hepatic participants. * History of any medical or psychiatric condition or disease. * Any previous procedure that could alter the absorption or excretion of orally administered drugs. * Body temperature greater than or equal to 38 degrees centigrade on Day -1 or Day 1 prior to dosing; history of febrile illness or other evidence of infection within 14 days prior to dosing. * History or presence of drug or alcohol abuse within 6 months prior to dosing; current tobacco/nicotine user; positive for alcohol and/or drugs-of-abuse at Screening or check in. * Participants who have received eculizumab at any dose or interval within the past 75 days. * Participation in any other investigational study drug trial 30 days before dosing. * Donation of whole blood from 3 months before dosing or of plasma from 30 days before dosing; receipt of blood products within 6 months before dosing. HI Participants: * Any acute or chronic non-hepatic condition that would limit the participant's ability to participate in this study. * Any other unspecified reason that would make the participant unsuitable for enrollment. * Any screening laboratory evaluation outside the laboratory reference ranges not related to HI. * Fluctuating or rapidly deteriorating hepatic function within the screening period and up to 30 days prior to Day 1. * History of chronic liver disease due to Wilson's disease. * History of liver or other solid organ transplants. Healthy Participants: * Clinical laboratory evaluations outside of the reference range at Screening or check-in. * Evidence of acute or chronic liver disease. * Use of any prescription medications/products within 14 days prior to dosing. * Use of over-the-counter, nonprescription preparations within 7 days prior to dosing. * Evidence of chronic HBV or chronic HCV infection.