The spike over $50 early this year was in anticipation of their first analysis for the IMPRESS pancreatic cancer trial for thieir hyperacute pancreas product. They did not reach statistical significance at that time and the trial continued. The next analysis point (333 events in the trial) is expected to hit around the end of this year. They have a pretty good chance of success this time because the hurdle they must overcome is lower (30% advantage vs 50% advantage) plus they will have had 10 additional months of follow up for each patient. The rate of events has been steady at around 10 per month which is slow for this disease. (this is my estimate and not that of the company)
The ebola outbreak throws a new wrinkle into the picture. This potential for substantial income means that the shares may never have a reason to go lower than they recently have (and may substantially increase). With a lot of profit potential gone, the shorts might be in a bit of a predicament.