Boxborough, MA location, applied last year. Applied as a referral. Hiring manager called and did a phone screen. One on-site interview. Fairly easy interview, one networking technical question. The main thing is that the interviewers wanted to make sure I understood the position and the challenges. After the single round of interviews (~5 people), ended up playing telephone/email tag for ~2 weeks until I found out that they were unable to match the compensation I requested.