Well, that was anticlimactic.

Shares of FireEye (NASDAQ: FEYE) rose around 2.6% last Wednesday, despite a significant lock-up expiration related to its recent secondary stock offering. FireEye has continued to rise from there, climbing another 9% between Thursday and this morning.

So why is this notable? FireEye already popped more than 10% earlier this week after Nomura analyst Rick Sherlund reiterated his buy rating ahead of the lock-up expiration.

The timing of the call was no coincidence, and seemed especially gutsy considering the expiration meant 82.2 million previously restricted shares were about to become eligible for sale. And remember, only two weeks earlier, shares of Twitter (TWTR) had plunged 13% following its own post-IPO lock-up expiration -- and this happened despite the fact that several Twitter executives had already confirmed they wouldn't be selling their stakes.

What made FireEye different?
Then again, FireEye's lock-up expiration "only" involved less than 57% of its common shares outstanding becoming eligible for sale, compared to a staggering 81% as part of Twitter's expiration. Moreover, Sherlund still insisted the stock could benefit from crossing this hurdle as anticipation of the lock-up had "dampened investor sentiment."

Of course, FireEye also didn't do itself any favors by providing weaker-than-expected earnings guidance in each of its last two quarterly reports, which unsurprisingly caused the stock to plummet each time. But as I noted two Mondays ago when FireEye reached out to plead its case to analysts at a self-hosted open house event, both drops were largely caused by significantly increased spending on research and development. And believe it or not, that's a fantastic thing to see for a high-tech company like FireEye, which is currently shuffling for market share in a fast-paced, burgeoning industry.

So where does that leave investors today?

To be honest, even with shares having risen more than 21% since last Monday, I actually like the stock right now, and think we've just witnessed a significant shift in sentiment in FireEye's favor. Heck, if we're lucky, the market may finally be ready to focus on its long-term story.

Foolish final thoughts
But make no mistake: This absolutely doesn't mean FireEye's volatility is finished.  Shares currently trade at an eye-popping 23 times trailing 12-month sales. And while FireEye has over $584 million in cash and short-term investments on its balance sheet, it's still losing plenty of money -- with a $101.2 million GAAP net loss last quarter alone -- as it forgoes bottom-line profits in favor of growing revenue.

Eventually, FireEye will need to show the market its R&D efforts are yielding fruit in its quest toward sustained long-term profitability. And if it can't, FireEye could easily force investors to endure plenty more pain. For now, though, with all things considered, I think the stock is definitely worth a deeper look for patient, long-term investors.