A Phase 1/2, Randomized, Double-Masked, Placebo-Controlled, Multicenter Study to Assess the Safety, Pharmacokinetics, and Efficacy of AMG 732 in Healthy Subjects and Subjects With Moderate-to-Severe Active Thyroid Eye Disease

Inclusion criteria for Part A/Phase 1 only: * Participant has provided informed consent before initiation of any study-specific activities/procedures. * Male or female aged 18 to 55 years (Part A). * Female participants must be of non-childbearing potential. * Body mass index (BMI) between 18 and 30 kg/m\^2, inclusive, at screening. * The participant has adequate venous access and can receive intravenous (IV) therapy. * The participant is considered by the investigator or designee to be in good general health as determined by medical history, clinical laboratory test results, vital sign measu…