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 Lululemon Athletica (NASDAQ:LULU) rose as much as 9.7% Thursday, then settled to trade up around 6.5% as of 2:30 p.m. after the yoga apparel specialist reported better-than-expected fourth-quarter earnings.

So what: Quarterly revenue rose 16% year over year (or 20% on a constant-currency basis) to $602.5 million. Total comparable sales climbed 8% for the quarter on a constant dollar basis, including a 5% jump in comparable-store sales and a 20% increase in direct-to-consumer revenue. That translated to a slight increase in net income to $110.9 million, and, thanks to lululemon's share repurchase efforts, a 4% jump in diluted earnings per share to $0.78. Analysts, on average, were only modeling earnings of $0.73 per share on slightly lower revenue of $602.4 million.

"Our solid performance in the fourth quarter builds on the momentum that began in the third quarter and reflects improved traffic and a strong guest response," added Lululemon CEO Laurent Potdevin. "2014 was a critical year when we strengthened our leadership team and made important investments in our product pipeline, guest experience, brand, and community engagement."

Now what: Going forward, however, lululemon expects current-quarter revenue of $413 million to $418 million, with diluted earnings per share of $0.31 to $0.33. Wall Street was looking for first-quarter 2015 earnings of $0.39 per share on sales of $442 million.

For the full year 2015, lululemon sees revenue of $1.97 billion to $2.02 billion, helped by a comparable-store sales increase in the mid-single digits. That should result in 2015 earnings per share of $1.85 to $1.90. Again, both ranges fell short of analysts' expectations, which called for 2015 sales and earnings of $2.05 billion and $2.06 per share, respectively.

On that note, keep in mind lululemon has a long-standing penchant for underpromising and overdelivering, so watching it issue conservative guidance is nothing new. In the end, as a shareholder myself, that's why I'm perfectly content knowing this solidly profitable company is still moving in the right direction after a difficult past two years.