testing it's 50 EMA

DXCM continues to cool off, down more than 5% on 6/4 Thursday. This stock is making a key test of support at the 50-day moving average and 10-week moving average. On the minus side, this stock had a shocking volume on 11th of May, but the share price only moved 3.9% and starts dropping since then.
the two support resistance levels are: $340 and $305.
about the company: develops glucose monitoring system.
last Qtr sales growth: +44%