This is a near classic double bottom base with a handle. Notice that during the handle relative strength increased while price decreased, indicating an imminent breakout attempt, all it needed was a surge in volume, which it got. Unfortunately, volume is decreasing as it hits new highs, which is a caution flag. This has 37.5 Million shares in the float, and 14% of the float short, so we could be seeing a short squeeze.
Charts courtesy of stockcharts.com