Recent developments might have scared away some investors, but patience could pay off.Over the past five years, diabetes-focused medical device specialist DexCom (DXCM -0.50%) has made meaningful progress on several fronts. The company launched new products in the continuous glucose monitoring (CGM) niche and entered new geographies. Its revenue has generally increased at a good pace on a year-over-year basis.However, after a recent plunge, DexCom has underperformed the S&P 500 in the past half-decade. Can ...