I don't know, as we haven't finished the first season! There has not yet been any word on whether Amazon has renewed it for a second season, but Sky Atlantic (who produce it) has, and apparently filming has begun.

The pilot is extra-length, but individual episodes are under 45 minutes long, so it's not that much of a time commitment when you're watching it streaming on your own schedule. We tend to watch two a night, two or three times a week. (We pretty much never watch shows while airing - we don't actually have television, and we don't like WIPs - so this is our MO for most TV.)