I submitted a resume through their website and had a phone interview within the week. The day after that, I received an invitation to an on-site interview. Total turnaround time was about 2 weeks, although I did tell them that I was going through another simultaneous interview process. The phone interview was straightforward and involved basic personality questions + technical background. Most of the questions were of the form "how well do you know X," where X ranged from design patterns to X86 architecture to programming languages. The on-site interview was a quick two hours, and involved a mix of brainteasers and technical questions, with the latter focused on low-level systems architecture. The biggest surprise was much my level of interest mattered; they're really looking for people who take the job seriously. Fortunately, I had done my homework and was well-prepared to talk about their previous projects.