Bourbon, I agree that it appears simple enough to cover 10m short shares over 2 years but it actually is not, especially if you want to cover REALLY LOW (which is the whole point of shorting).
As Ig indicated in another post, funds like Adage enlist MMs to do their dirty job, which is to collect falling shares from retail, and take them over in BULK (so they can disclose their increased position at once and not tip off their incremental share collection to the market).
Approximately 95% of trades every day (averaged over the last 2 years with exception days), as you can clearly see on level 2, are back and forth trades between MMs themselves. They are fishing relentlessly for falling shares but they are not getting all they need. As it happens, there are a big bunch of longs here with big holdings who are simply refusing to budge. I see that their only way out to is to cover from their box or convince ADXS to bail them out with a private placement.