From a slightly longer time perspective than many seem to hold around here, ARM looks very dodgy.
Here is your chart with some of my squiggles on it.
The Bull Trend (3)has been broken, along with the immediate support at 370. This has led to a test of the major support area at 320/330 which, so far, has held.
The failure to make new highs or to break back above 420 allowed us to draw in a Phase 1 (Disbelief) long term trend (1). We then move into a more realistic Phase 2 (Reality) bear trend (2), having had a bit of Phase 3 (OmiGodHelp) trend - the unsustainable drops or rises that lead to retracement.
The current retracement has moved back to retest the old support (370) which has now become resistance (Dead Man's Knock) and confirm a more sensible trend angle. I would expect to see a continuance under this trendline to at least retest the 330/20 area, and perhaps beyond to retest the base at 190/200 - ugly stuff.
On the positive side, the only thing that would convince me to go long ARM (depending on yr time horizon) would be a break above 420. I would rather be short than either flat or long, with a stop ready to go on the break of the major trend (1) - so currently a close above 410, but again, it depends on your risk/reward/time ratio as to how you would personally trade this.
But, for me, ARM looks like a sick puppy at the moment.