OK, I appreciate your response. Basically I think you are saying that the deal was expected and the deal seems favorable to IDIX. Therefore the default explanation for the price drop is the "sell on good news" strategy.
A follow on question: Does this deal make it any more or less atrractive for Novartis to buy out the minority shareholders? I would think it makes it more attractive because a piece of the pie is carved out that strategically probably has more value to GSK than Novartis. The pie is a little smaller but presumably cheaper now.