If I was looking to get long, I would lean against 14.00 and stay long as long as that level holds. I would stop out under 12.00.
The 20 level is the next obvious level of supply, but after that it is pretty open.
Gopro has underwhelmed investors since going public, hence the steep slide. In my view, stock prices reflect the companies future earning potential weighed against expectations.
As always, have a plan before you go into a trade. I always find a checklist useful.
4.I am going long/short because X....
Writing things out will help you go back and evaluate your thinking.