1. Offline coding test. You get 24 hours to write a program and send it back to them.
2. Phone interview with a math question.
3. On site interview with 6-7 people. The atmosphere is very elitist, touting the fact that they have Stanford, Caltech people. They spend more time putting you through C++ terminology questions, hypothetical how you write an algorithm scenarios, and 100% off topic brain teasers than they spend discussing anything relevant to the position, just to make sure you are brilliant enough to do the job of finding bugs in other people's code.
Most people are ok, but a few came off very condescending.
Very fast and efficient at the interview process, but at the same time this is a huge time sink for the candidate compared to other companies.