It went all the way back to just over $2. You're looking at a selectively small time period if you're saying the bubble burst and it fell to just $17.
the fall from 15$ to 2$ was because of hacks and such totally killing confidence, i'm not sure what event could possibly shake confidence at this point...
The biggest problem for this price bubble is that the price is only determined by a few amateur-like exchanges. Right now it rises steadily, so people log in occasionally. What if suddenly there is a big price drop ? Then everyone will want to log in and frantically place orders, making the sites crash and unreachable. And it'll feel terrible when the price goes into a free fall while you can't log in to sell. Not to mention the constant DDOS-ing by shady parties trying to manipulate the price.