I had phone interviews with two different managers, both lasted about an hour. Phone interview was based on my PhD thesis, basic compiler theory and basic C++. Then I was called for an on-site interview at San Diego. I had to give a talk in front of the interview panel. Then I met 5 managers, including 1 lunch interview. Finally met the HR which was just about overall experience, expected salary etc. The 1:1 interviews were mixed. They did not look very prepared or organized. I had to switch between rooms for one 1:1. One interviewer seemed bored and uninterested, working on other stuff while I was answering questions. He/she also assumed I am from a specific country which I am not. This interviewer looked very unprofessional to me. The lunch interviews are awkward and IMHO a bad idea. My final two went exceptionally well. The director was nice and encouraging. But I got no offer at the end, which was expected given the majority of my interviews were not great.