Dexcom (NSDQ:DXCM) shares took a hit after hours today despite first-quarter results that beat the consensus forecast.

DXCM shares were down -5.2% at $400 per share after hours. MassDevice’s MedTech 100 Index — which includes stocks of the world’s largest medical device companies — was down -0.8%.

The San Diego-based glucose monitoring technology developer posted profits of $40.3 million, or 41¢ per share, on sales of $505 million for the three months ended March 31, 2021, more than doubling its bottom-line on sales growth of 24.7%.

Adjusted to exclude one-time items, earnings per share were 33¢, 3¢ ahead of Wall Street, where analysts were looking for sales of $484.2 million.

“Dexcom is off to a great start in 2021, including several key advancements of our strategic priorities in the first quarter,” Dexcom chairman, president & CEO Kevin Sayer said in a news release. “Based on the strength of our first-quarter results and the significant market opportunity ahead of us, we are pleased to raise our 2021 revenue guidance.”

Dexcom said it now expects to log full-year 2021 revenues of between approximately $2.26 billion and $2.36 billion, representing growth between 17% and 22% year-over-year.