Print Sometimes a company reports better-than-expected financial results and its shares still sink, as San Diego’s Dexcom found out this week. The maker of wearable continuous glucose monitors reported first quarter revenue late Thursday of $505 million, up 25 percent over last year and above the $487 million average prediction of Wall Street analysts. For earnings, Dexcom posted net income of $40.3 million, or 41 cents a share, under Generally Accepted Accounting Principles — ahead of analysts’ GAAP forecast of 29 cents per share. Yet the company’s stock price dropped 8.4 percent in Friday trading, shedding $35.60 to close at $386.10 on the Nasdaq Exchange. Advertisement Investors appeared spooked by competitive pressures in the continuous glucose monitoring market, and by Dexcom’s high valuation based on a recent surge in its stock price, said Kyle Rose, an analyst with Canaccord Genuity.