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 Alliance Fiber Optic Products, Inc. (NASDAQ:AFOP.DL) jumped more than 12% Wednesday after the optical network equipment specialist announced encouraging preliminary first-quarter sales results.

So what: Quarterly revenue is now expected to rise roughly 104% year over year to $24.8 million, or 10% higher than the $22.5 million guidance Alliance provided in early February. As a result and without providing specific numbers, Alliance says it expects to report record quarterly profits as well. 

Analysts on average, were modeling first quarter earnings of $0.27 per share on sales of $22.53 million. 

Now what: Those estimates should increase as analysts have time to fully digest today's news, so the stock could still prove a bargain, with shares currently trading at just 14.5 times next year's expected earnings. However, keep in mind we're also talking about a relatively small company whose modest revenue base could be subject to wide swings. As a result, while I wouldn't be too anxious to sell any existing shares after today's pop, investors may consider treading lightly when opening new positions until we receive more color on Alliance's first quarter results on April 24.