Well, you missed some keys in your story:
After the 2012 secondary announcement, EXEL's trading price was down to $4.85 on Aug 6th (20% drop), $4.58 on Aug 7th (6% drop) and $4.28 on Aug 8th (7%.drop).
This time (2015), after the secondary offering announcement, we only see about 1-2% price action right now. So the offering price will be more likely around $5.88...
Well, we can only speculate:
1. They don't have any offer on the table and don't expect it any time soon.
2. They need cash to pay off some of their obligations.I remember that they may have about $60M due next couple of month.
3. They need cover some expense for possible cobimetinib launch.
Our only hope is that maybe the big boy already knows and the large amount of short interest can offset some of the offering.
Well, I read it about 2 years ago when they announce the partnership:
1. Exelixis will get abut $100M for the approval.
2. Exelixis will get 50% of the first $200 million of US sales (decreasing to 30% of sales over $400 million).
3. Exelixis will get about 15% profit from outside the US.