Folks in these type of sell-offs, there is only one question you need to ask yourself.
Has the business case for CELG changed? It did change actually for the better. Even if it stayed the same the business case for CELG is compelling. Eventually, these nonsensical selloffs get corrected. I think it will get corrected quick...so I wouldn't be out of the stock. I'd buy more, laugh at the fools selling and sleep like a baby. Just my HO.