This multi-center, fixed-sequence, open-label, multiple-dose, 2-period study will evaluate the safety, tolerability and pharmacokinetics of setrobuvir alone or in combination with ritonavir-boosted danoprevir in subjects with mild hepatic impairment compared to healthy controls. All subjects will receive multiple doses of setrobuvir orally for 10 days in Period 1 and multiple doses of setrobuvir plus ritonavir-boosted danoprevir orally for 10 days in Period 2, with a washout phase of at least 9 days between treatments.