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 Criteo SA (NASDAQ:CRTO) fell more than 10% early Tuesday after the performance display specialist released first-quarter results.

So what: Quarterly revenue increased 60.8% to $212.49 million, which translated to adjusted net income that more than tripled to $10.59 million. Revenue excluding traffic acquisition costs -- which management states is a "key measure" they use to evaluate operating performance and provide useful period-to-period comparisons for their core business -- grew 68.2% to $87.37 million.

Criteo also said it expects that second-quarter revenue -- excluding traffic acquisition costs -- should arrive in a range between $85.69 million and $88.48 million, the midpoint of which represents relatively flat sequential growth.

Now what: In the end, though, we're talking about a barely profitable $1.6 billion company with a history of stubbornly high short interest, and I still think investors need assurance that Criteo's past torrid rates of top- and bottom-line growth are sustainable over the long term. For now, that's why I'm perfectly happy remaining on the sidelines.

Steve Symington and The Motley Fool have no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.