I had a 30 minute to hour-long technical interview with an engineering manager. She described the internship's tasks and then asked me a couple technical questions. After that went well, I spoke with the senior engineer who would supervise me during the internship. I came in for an on-site interview that lasted around 2 hours and received an offer the same day. The manager/interviewers I met were very warm and sociable. The company atmosphere was fairly relaxed, which helped alleviate a lot of the stress that can be present during an on-site interview.