I'm sure they watch the stock price closely, as evidenced by their rebutal to the DR original leak. I can tell you that a potential buyer will probably bid based on it whether they-IDCC like it or not.
During the six years I've been in this stock, I have never known the BOD to be very concerned about the stock price.
The board and management have a very firm idea of how they value InterDigital's patent portfolio, and I can't believe they would let daily stock price (which is and has been subject to easy manipulation) impinge on their decision. This is not a typical takeover situation. I guess that has become obvious to everyone, long or short, fan or basher.
Current PPS will determine buyout price whether or not board likes it. They have to decide if they will adjust their thinking. The fact that they have not ended talks inidicates they have adjusted or are just being silly and stubborn. I sure hope its the first.