Three 30-60 minute phone interviews over the course of three weeks. The first was with HR, and the other two were with people who were either in the position I was applying for or overseeing it. After interviews were set up, there were a lot of last minute changes, and the interviewers did not always seem aware of the office I was applying for or my background, which made it seem messy. Due to patent constraints they weren't able to fully explain some details of the job, either. Every person was very friendly, and some of the conversations were even intellectually challenging (in a good way!). Everyone seemed to come from diverse, but very interesting backgrounds. After the third interview, I was told the position had already been filled. I'm guessing that they hire on a rolling basis and try to find the quickest good fit as opposed to a perfect fit comparing various people.