Last Week's Biggest Movers on Wall Street

Plenty of stocks go up and down in any given week. The gainers inspire us to keep investing. The decliners keep greed in check while reminding us about the risks of the equity markets.

Let's go over some of last week's best and worst performers.

Vitae Pharmaceuticals (VTAE) -- Up 88 percent last week

The market's biggest gainer last week was a biotech company that got some good news on an early-stage clinical trial. Vitae's VTP-43742 is an inhibitor being developed to treat a wide range of autoimmune disorders that could potentially include psoriasis, psoriatic arthritis, rheumatoid arthritis, multiple sclerosis and irritable bowel disease.

The test is still in the first of three clinical trial phases, and as any biotech investor knows, things can always fall apart in later trial stages. However, with so much riding on the potential treatment, it isn't a surprise to see the stock take off after an upbeat test -- just as it could give it all away and then some if things don't go well in the next phase.

Dave & Buster's (PLAY) -- Up 16 percent last week

Shares of Dave & Buster's hit the jackpot after the chain of "eatertainment" restaurants posted blowout quarterly results. Comparable-restaurant sales soared 11 percent since a year earlier, and the strong showing finds it boosting its guidance for all of 2015.

Dave & Buster's went public at $16 late last year, and it has gone on to soar 167 percent. It hit another new high last week.

JinkoSolar (JKS) -- Up 13 percent last week

Solar energy stocks tend to run hot and cold, but JinkoSolar came through with a bright week, posting double-digit gains. The provider of solar cells, modules and other related solutions introduced a new line of photovoltaic modules with integrated single-chip electronic optimization. JinkoSolar also took out a credit line with a major Chinese bank, arming itself with the means to ramp up production.

Cherokee Global Brands (CHKE) -- Down 42 percent last week

%VIRTUAL-WSSCourseInline-704%Sometimes you miss the Target (TGT) in more ways than one. Brand marketer Cherokee posted year-over-year declines at both ends of the income statement in its latest quarter, but the real dagger was the revelation that Target won't be renewing its license of the Cherokee brands in the U.S. when it expires in early 2017.

That's a pretty big deal, since most shoppers of Cherokee-branded apparel associate the brand with the cheap-chic retailer. This will end a licensing relationship -- and royalty-generating stream for Cherokee -- that has lasted for roughly two decades. Target also has a licensing agreement with Cherokee for the Liz Lange brand and that remains in place at this time.

Mattress Firm (MFRM) -- Down 22 percent last week

It was hard for Mattress Firm investors to get any sleep after a poorly received financial report. The retailer of bedding products may have seen sales soar 61 percent in its latest fiscal quarter since the prior year, but that is largely the handiwork of sector consolidation in a highly fragmented niche. Mattress Firm loves to gobble up smaller, regional mattress chains. It's now up to 2,223 stores under its belt. Comparable-store sales were positive, but up a modest 2.8 percent.

Mattress Firm's operating margins declined, with adjusted earnings ultimately falling short of analyst forecasts. Mattress Firm is lowering its earnings guidance for the entire fiscal year. It's also discontinuing its Mattress Pro concept.

Barnes & Noble (BKS) -- Down 21 percent last week

The last major retail bookseller turned into a hard read for its shareholders after posting disappointing quarterly results. Sales at Barnes & Noble's namesake stores and its Nook e-book operations slipped 3 percent since the prior year to clock in at $994.3 million. That was less than what analysts were expecting.

Sales may have risen at the individual store level -- new releases by Harper Lee and E.L. James will do that -- but store closures, a surprising drop in online sales and the Nook's continual fade weighed on results. Barnes & Noble spun off its college bookstore business last month and that's rough since it was the only segment of Barnes & Noble to post year-over-year growth for the period.

Motley Fool contributor Rick Munarriz has no position in any stocks mentioned. The Motley Fool owns shares of Barnes & Noble and recommends Dave & Buster's Entertainment. Try any of our Foolish newsletter services free for 30 days. Check out our free report on one great stock to buy for 2015 and beyond.