Phone interview comes first. Some basic background questions and SAS questions will be asked.
The onsite interview is usually scheduled 1-2 weeks later after phone interview. They will ask you to present one of your former projects to them and they will raise questions based on your project. Statistical heavy. So your project should be statistics related.
After onsite interview they will let you to talk to the managers and other team members to see your personality. After all these they will let you know if you are getting the job or not. Usually it is fast.