Recruiter contacted me through LinkedIn. One phone IV with team lead, then onsite in Bay Area. There were five interviews. All asked mostly questions about my work, and some basic programming questions. All grilled me on register allocation. If you work in a specialized field, don't expect to be treated like a new grad. Research the subject matter outside of your bubble at work and things will go more smoothly. Make sure you can generalize without referring to your team's specific data structures.