Yoga gear retailer lululemon athletica (Nasdaq: LULU) is on fire these days. Shares of the high-end activewear chain traded as much as 8% higher today after the company posted better-than-expected quarterly results.

Net revenue soared 69%, to $138.3 million, fueled by healthy expansion and a whopping 35% spike in comparable-store sales. Yes, that's 35% on a constant-dollar basis for the Canadian-based retailer. And you thought lululemon's 29% surge in comps was impressive a quarter ago!

Earnings tripled to $0.27 a share, even though the company bumped up its effective tax rate to 40% to clear the way for earnings repatriation. Analysts were only banking on a profit of $0.21 a share, with $128.2 million on the top line.

The key to lululemon's success is its popular collection of performance apparel. These togs are a fashion fit whether its wearers are running errands, working out, or stretching through a yoga session.

Witness the magic of premium-priced wares in demand: lululemon has generated average sales per square foot of $1,428 over the past four quarters.

That number may not mean much to you, so let's head to the mall. Taubman Centers (NYSE: TCO) claims to run the most productive malls in the country. Its tenants have averaged $509 in sales per square foot over the past year. In other words, lululemon is nearly three times as productive as the typical Taubman store. Market-leading mall operator Simon Property Group (NYSE: SPG) is clocking in at $467 per square foot over the trailing 12 months.

Is lululemon the star of the mall in monetizing its space? If there isn't a higher-grossing Apple (Nasdaq: AAPL) store in a lululemon-occupied mall, it may very well be. This, in turn, makes lululemon a highly coveted tenant for mall operators eager to boost sales metrics and fill vacancies.

lululemon's guidance for the year now calls for between $1.05 and $1.10 a share in earnings, on $620 million to $635 million in net revenue.

If investors expect to pay a premium to get in on this glitzy retailer, they would be absolutely -- positively -- correct, unfortunately. The stock opened today at 37 times the high end of lululemon's projected profitability for this year.

Consumers don't have a problem paying a premium for branded performance apparel. Nike (NYSE: NKE) has made a comfortable living. Under Armour (NYSE: UA) -- perhaps the better fit relative to lululemon -- is another winner here, with its sweat-wicking apparel.

The market is pricing Under Armour at roughly 30 times this year's earnings target, even though lululemon is growing substantially faster. In other words, lululemon may not be all that ridiculously priced, especially given its early position in the growth cycle.

It's the fastest-growing apparel retailer I've seen these days, and shareholders -- like consumers -- know that you have to pay a premium for something that works.

Do you know a hotter retailer? Prove it! Top lululemon in the comments box below.

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Longtime Fool contributor Rick Munarriz doesn't think he's cut out for yoga, given his inability to relax and focus. He even lacks the patience for yoga through Wii Fit. He does not own shares in any of the stocks in this story. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.