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: Beleaguered Westport Innovations (NASDAQ:WPRT) investors should be happy today, with the stock up 10% as of this writing on heavy trading volume that is nearly three times the average over the past few months. No specific Westport-related news is driving the stock, but many other volatile growth-focused companies are seeing shares trade higher on an improved global economic outlook. 

So what: Westport Innovations is scheduled to report third-quarter numbers on Thursday, so there's probably some pre-earnings buying happening as well, even though the company said at the beginning of October that the numbers wouldn't be great. Westport cited softness in its core business in Europe and Asia, problems with a large order of its LNG fuel system, and delays in production of its high-pressure, direct-injection -- or HPDI -- technology with several OEM partners, largely due to the transition to the second generation of the technology, called HPDI 2.0. 

Now what: Frankly, no news is no news. If you're a shareholder with a long-term outlook, there's nothing to see here besides Mr. Market doing his thing. If you're considering opening a position (or adding to an existing one), the stock is still well below where it was just a month ago, and down more than 82% from the 2012 peak. This probably isn't a good time to go "all-in," but rather to start small and look to the quarterly earnings results, along with announcements from development partners to determine how the business is performing. 

At the end of the day, the company needs to return to growth before the stock price rebounds in a meaningful or sustainable way.

Jason Hall owns shares of Tesla Motors and shares of and options for Westport Innovations. The Motley Fool recommends Ford, Tesla Motors, and Westport Innovations. The Motley Fool owns shares of Ford, Tesla Motors, and Westport Innovations. Try any of our Foolish newsletter services free for 30 days. We Fools may not 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.