Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of DexCom Inc. (NASDAQ:DXCM), a medical device company focused on creating continuous glucose monitoring systems, skyrocketed as much as 27% after reporting its second-quarter earnings results.

So what: For the quarter, DexCom delivered a huge surge in revenue -- 53% to be exact -- to $35.8 million, although product revenue was the real star, up 65%. The company's quarterly loss narrowed by a third to $0.14 per share from $0.21 per share in the year-ago period, but includes quite a few one-time expenses. With those pulled from the equation, DexCom lost just $0.02 per share on an adjusted basis. Comparatively, the Street had expected revenue of just $31 million and an EPS loss of $0.15.

Now what: I have to eat some crow here and admit that this quarter was a lot better than I anticipated from DexCom. On paper, DexCom's potential market is huge with some 25 million people in the country living with diabetes and close to 80 million others in the pre-diabetic stage. However, my initial contention that DexCom's surge is occurring without any bottom-line profits remains valid. Revenue growth is surging and losses are narrowing, but we've yet to see DexCom report a profit -- and it may still be a while before this happens given the fierce competition within the sector over monitoring devices. As such, and following such a huge run higher, I'd suggest sticking to the sidelines until such time as DexCom can put its business in the black.