Only short if you have a strong stomach or dramamine. This stock can punish you big time, so do NOT go in short with a lot of money. Be ready to deploy more if it really runs up. Although I am short now, I do think it could run all the way up to $300 again in this insane market. Nothing is normal right now. You have companies that are not earning money and do not expect to earn much over the next few years trading at crazy levels, but those levels just keep getting higher. You should probably take a pass on shorting this.
Depends on your time frame...for TODAY, I would say right about now people will start taking profits on a pretty big move today...if you are talking longer term, I would say wait until this tests its 52 week high and maybe even the all time high of 304...that could potentially be "the short of the century"