This medical device company is down but not out.Is the sky falling for DexCom (DXCM 0.89%)? Shares of the medical device specialist dropped off a cliff following its second-quarter earnings report. Unfortunately, the diabetes-focused company failed to impress investors yet again with its most recent quarterly update.At about $69 per share, DexCom's stock isn't that far off its 52-week low of $62.34 and is miles away from its 52-week high of $142. However, there remain good reasons to invest in the company.D ...