They sold to cover taxes owed on options granted. This was clearly spelled out in the form 4. Overall net ownership went up. I would be more crtitical if they had not sold and payed the tax. Not selling would have shown a serious lack of judgment.
Last year SNSS failed the P3 and went to $1. Short version they submitted to FDA anyways and went back to the 3's. Xoma saw drug interaction and may being going ahead with submitting the BLA. Can't think of any other reason stock price is going up.
XOMA (NASDAQ: XOMA) shares re active early with the stock rising over 4 percent on heavy volume.
UPDATE - XOMA could be moving as traders began passing around an old article from Stock Gumshoe. In part, the article highlights a $143 price target on XOMA issued by Biotech Insider Alert.
Notably, the article is from November 2014, though it wasn't made clear whether an updated report was released since then.