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 Pacific Biosciences of California (NASDAQ:PACB), a life sciences company focused on developing single-molecule real-time genetic analysis platforms, surged as much as 16% intraday during Friday's trading session after receiving an upgrade from a Wall Street firm.

So what: Research firm William Blair announced this morning an upgrade to Pacific Biosciences' stock to "outperform," or the equivalent of "buy," from "market perform," or what is essentially a "hold." No price target was issued with William Blair's rating change. The move comes just days after announcing a number of new targeted sequencing applications spurred by the company's collaboration with Roche, and just four days before being scheduled to report its first-quarter earnings results.

PacBio RS II. Source: Pacific Biosciences of California.

Now what: Today's upgrade was a pleasant surprise for Pacific Biosciences, or PacBio, shareholders who'd seen just a single green arrow in the prior 11 trading sessions. However, Wall Street rating changes often have the smell of being decidedly short-term in nature, meaning they rarely have any long-term impact on stock prices.

Ultimately, investors are going to want to see top- and bottom-line improvements in PacBio's results before its share price has any shot of heading notably higher.

On one hand we've already witnessed some steady progress, with quarterly losses regularly in the $0.20-$0.28 range per share instead of $0.35-plus in 2012 and early 2013. It shows that growing system sales and prudent spending is helping to stretch PacBio's remaining dollars even further. Additionally, PacBio is in line to benefit from a growing trend of treatment personalization, which is what its genetic analysis solutions are designed to cater toward.

Of course, investors also need to realize this is a long-term type of holding that's unlikely to be profitable for many years to come. It certainly has the technology and a formidable collaboration partner in Roche to be successful, but its upside could be limited by its ongoing losses and its inability to chip away giant chunks of its operating losses at a time.

Personally, I'd prefer to keep PacBio on my watchlist for future reference, but I wouldn't suggest chasing it any higher following William Blair's upgrade.