Hard to say exactly what this is.  Unlikely that it is all shorting since the price is already down 40%.  Prices are starting to look attractive but the decline is consistent.  This could still be a "catch a falling knife" situation.

Comparing the Amarin chart to the RVX chart ... looks pretty different...AMRN sat in roughly a +/- 20% range for the 6 months leading up to the results.  We should be a couple months into that period now unless there are other delays, and RVX is much more volatile.