A standard interview process for a mid-level position includes a phone screen, a round of on-site interviews with 4-5 people, then a second (possibly third) round with senior management. Both technical knowledge and cultural fit are essential. You have to come strong on your understanding of financial statements/accounting and how they relate to the business, how you were able to lead and make an impact in your prior jobs (even if you were not in a management role). Also, a positive attitude is very important, the company is fast-paced so it is key to have people who embrace change. Do not BS though, they will see right through it... Do your homework, you should show genuine interest for what Illumina does and become acquainted with the technology... Finally, reading the 10Q and 10K is always a good idea...