I sure hope 5 doesn't hold and I'm sure I'm not alone in wanting cheaper shares back again :-).
Quick answer experience and a little luck :-).
I looked at Acadia a couple days prior to it exploding to mid 7's and passed on buying. OUCH...
Relying on my DD used in passing on the stock, I felt it got very overbought and shorted 15,000 shares. I felt the stock could sell off below 4, but covered after a small .20 cent bounce off 4.18. The best part was going long as the stock bounced thereafter and I sold $5.14. However, I chose not to short again and based on my DD and gut if you will, I decided I'd buy again if I got my price target of 4.60's to 4.70's.
The company has great potential, but I believe it's priced at fair value in the mid 4's, given we are a very long way off before FDA even takes a look see.
Sorry if you were looking for a more technical answer. Been trading since 97 and doing well, but in the end, it's all a gamble.