Very extensive. There were three rounds of interviews. The first round is the basic behavioral and background questions. The second round isn't actually an interview it is a case study. The third round is just them going over the case study and then you either get an offer or you don't. They were at a career fair at my school so that is how I got the contact information. You also talk to the same level people throughout the process. Two of them were over the phone and the third was a video interview through google hangout.