I knew someone who knew a manager in the company who was looking to build his team, and I got in touch with him. After a couple of informal phone interviews to talk figure out whether the kind of work matched what I was looking for, they brought me in for an on site interview. I gave a (short) 30-minute job talk. Then I stayed in the conference room when others came in to interview me one-on-one. We discussed my background, my skills, what kind of work I would like to be doing, how I felt about working in groups, etc. They couldn't discuss about what they were working on in detail even though I had signed a NDA. The interview started at 9am and ended by 3pm.