"mgt/investor relations need to say something about this UNUSUAL activity in the stock" Really?
Maybe it can just be chocked up to investors, in the aggregate, including hedge/mutual funds, simply positioning themselves for 2014. It could be just that simple. You have to know that mgt of any co. never comments on movement in share price, in the absence of meaningful news. And yes, the floor could drop out; that's true of most any biotech stock.
But, when you look on Xoma's website, you'll notice that there are a number of job postings (at least there were) related to the prospect of Gevo being a bonafide drug with needs for sales/marketing/quality & control. They are counting on things moving forward with Gevo.