Phone screening with hiring manager was a traditional "talk the talk" interview with some technical and brainteaser challenges; then a half-day on-site interview with engineering team members and hiring manager including "walk the walk" tasks including design, programming, and more brainteasers; then followup phone interviews/conversations with one east-coast engineer and CEO. 21 days from first contact to verbal offer, but pretty good followup and great communication in between each stage.