Dexcom Inc. (NSDQ:DXCM) shares closed down a hair today despite Wall Street-beating preliminary 4th-quarter sales numbers for the medical device company.

DexCom said it expects to report sales of roughly $51 million for the 3 months ended Dec. 31, 2013, a 61% surge over the same period last year and well ahead of the $46 million forecast on The Street. Full-year sales are pegged at $157 million, representing a 69% gain over 2012.

The results, released ahead of CEO Terry Gregg’s presentation today at the J.P. Morgan Healthcare conference in San Francisco, were accompanied by product revenue guidance for fiscal 2014 of $205 million to $225 million, according to a regulatory filing.

The news sent DXCM shares down 0.9% to a $36.92 close today, perhaps driven by the expectation that the pace of DexCom’s growth is set to slow, according to Leerink Partners analyst Danielle Antalffy.

"With revenue growth set for deceleration in 2014 and beyond – albeit still strong double-digits – it’s becoming increasingly tough to argue for further multiple expansion from here. Longer term, we believe key technological advances such as communication with mobile devices and/ or the elimination of finger sticks – possible with Gen 5 or Gen 6 – will be the key to driving the paradigm shift for CGM from a ‘nice to have’ mindset to a ‘must have,’" Antalffy wrote this morning in a note to investors. "We expect: (1) FDA approval of a G4 pediatrics indication in early 1Q14; (2) Animas Vibe U.S. approval potentially 2H14; (3) Tandem Diabetes/G4 combo product approval in late 2014/early 2015; (4) DexCom Share system approval in 2014; and (5) G4 Professional approval in 2014."