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 Quiksilver (NASDAQOTH:ZQKSQ), which briefly topped a gain of 15% this morning before slipping back, have surged again in early after-hours trading to a gain of nearly 12% on the outdoor-sports clothing retailer's solid earnings  report.

So what: Quiksilver's first-quarter revenue came in at $341 million, down 14% year-over-year in nominal terms and down 4% on a constant-currency basis. The company's adjusted EBITDA fell from$16 million in the year-ago quarter to $10 million in the latest quarter, but its losses per share shrank from $0.13 a year ago to $0.11 in the latest quarter. Both top- and bottom-line results surpassed Wall Street's expectations, which had sought $337.4 million in revenue and a loss of $0.14 per share.

Quiksilver also offered guidance for the upcoming quarter and for the full fiscal year. It is now projecting $340 million in second-quarter revenue and $8 million in adjusted EBITDA. Full-year revenue is expected to range from $1.38 billion to $1.45 billion, with full-year adjusted EBITDA ranging from $70 million to $80 million. Both quarterly and annual revenue projections are weaker than Wall Street's expectations, as analysts had modeled $368.6 million in second-quarter revenue and $1.49 billion in full-year revenue.

Now what: Quiksilver's stock has been one of the worst on the market over the past year, even after accounting for its double bounce today. Shares have lost three-quarters of their value since last March (including tonight's after-hours pop), but that's to be expected of a company that has yet to return to growth in its core metrics after years of fundamental backsliding.

Quiksilver's revenue has fallen by 20% since mid-2012, and both EBITDA and EPS have collapsed from positive territory into deep losses since that time. Forward guidance continues this trend on the top line, as the company reported $1.57  billion in revenue for its 2014 fiscal year. However, Quiksilver's EBITDA guidance range is a big upgrade over 2014's result of $39 million, so there does appear to be improvement in the company's cost controls, even if consumer interest has not yet rebounded. This bottom-line improvement might be enough to attract short-term speculative interest, but Quiksilver can't be considered a legitimate long-term retail investment if its top line continues to decline.