After analyzing the impact of Abbott's (ABT) FreeStyle Libre approval and Medtronic's (MDT) 670G rollout, Piper Jaffray analyst Matt O'Brien believes competitive fears for Dexcom (DXCM) are overblown. The ultimate impact on Dexcom from these technologies "will be less than feared" as FreeStlye Libre is unlikely to get a non-adjunctive claim and the 670G roll out will be slower than expected, O'Brien tells investors in a research note. He expects this to drive multiple expansion for Dexcom shares. The analyst upped his price target for the stock to $87 from $78 and keeps an Overweight rating on the name.

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Pre-earnings options volume in DexCom is 11.4x normal with calls leading puts 11:2. Implied volatility suggests the market is anticipating a move near 5.8%, or $8.05, after results are released. Median move over the past eight quarters is 5.4%.