great stock can get you 7% a year ROI, 100% in 4 days is unreal. Revenues had to go up 500% to justify that change and I can;t see that anywhere. Don't buy in, wait, if you have a position shares sell some. or just keep what you have and see what will happen but don't get sucked in. they can drop the bid 20% in a second.
Opk is valued at staggering 2.25 billion, they yet to make a profiye on thier 50 million a year revenues. watch out, keep your finger ready as this is not your avarage stock anymore.