Not sure of the reasons. Could be just normal disappointment with the time it takes to build a new drug like spinraza. That kind of thing happens a lot with new drugs and the companies involved.
I'm not a person that relies on TA but I do use it and when I look at the ions chart it sure looks it's tracing out a head and shoulders pattern. A break below the neckline would imply a measured move down to 26. That seems really low and I would be buying probably before it got there but that's what I see when I look at the chart.
A move above 50 would make me think the head and shoulders pattern risk is probably gone and that the stock could move to new highs.