I applied online, and a week later, I received an email from an engineering fellow about a phone screening. He asked me what type of work I was interested in, and explained their work. He liked my responses, so arranged to fly me out for an on-site interview. HR arranged all the travel and stuff for me, and I arrived in Marlborough the afternoon before. The directions to the site were a bit trickier than I thought, so I arrived a few minutes late.
I had four interviews with four managers. First one just talked at me, but the second guy was pretty excited about technical questions, which covered a whole range (waveforms, networks, coding, filters), and third guy was kind of behavioral. Fourth interview was also just chatting, mainly about life in Massachusetts. I had lunch with one of the junior engineers, officially not an interview, and then had a follow up with the recruiter, who said she'd be in touch with me within a week. This was a Wednesday. I received a call from her on Monday, and the offer package arrived on Tuesday.