It signifies that they want more information on your family details.
The PR application will take as long as it needs. About as long as a piece of string? Unknown. Is your family a cloned family, e.g., all details are exactly the same as everybody elses family? Of course not. Therefore, it's impossible to gauge how long it will take. At this juncture at least you haven't been rejected yet. So just bide your time and all will be revealed when it's ready. Meanwhile, when you do get more information, let us know what & when. It's the only way our other readers get any anecdotal evidence.
I reckon you will probably get a please reapply after you have been here for 2 years letter. But stranger things have happened.