Organovo Holdings (ONVO -2.91%) was one of last week's biggest winners, soaring 55% after making the leap to the more prolific NYSE MKT exchange.

A bigger stage plays well when you have a neat tale to tell, and Organovo certainly has all of the makings of a hot story stock.

Organovo takes 3-D printing to a seemingly implausible extreme. Its bioprinting process can generate a reasonable proxy to human tissue in a lab that can be used in culture plates or bioreactors for medical research and therapeutic applications.

Yes, that's pretty cool, and recent investors seeing the stock jump from $3.87 to $6.01 in a single week have a good reason to get giddy.

Unfortunately, long-term investors have seen this before.

The stock traded as low as $2.35 in May of last year, only to peak at $10.90 a month later and bottom out at $1.49 the month after that.

Organovo is a volatile little specimen, and it can thank 3D Systems (DDD 0.57%) and Stratasys (SSYS 0.61%) for all of the attention.

3-D printing wasn't on the investing radar until last year when 3D Systems and Stratasys made it fashionable. Manufacturing printers capable of cranking out on-demand aircraft parts, prosthetics, orthodontics, and even your nephew's missing Lego piece is no longer the handiwork of science fiction. Sure, the printers are slow as molasses and pretty darn expensive, but we've seen technology get faster and cheaper over time.

Office supply chains are starting to stock 3-D printers. The mainstream push is coming.

Stratasys shares soared 164% last year, and they come off as slackers compared to the 284% pop for 3D Systems.

Their Wall Street success has spawned interest in other companies with 3-D printing models, though clearly there's a major difference between the reality that 3D Systems and Stratasys have achieved and the unfulfilled yet lofty ambitions of Organovo.

For now, the wild swings are fueled by speculation. Organovo isn't generating any kind of meaningful revenue. It cranked out a mere $0.2 million in revenue during the first three months of this year, and half of that was the result of grant revenue.

There will be more rallies like we experienced last week, and it wouldn't be a surprise to see the company try to shore up its balance sheet by raising new financing during the good times. There will also be more crashes like we had last summer, and the "I told you so" will sting until the story stock regains its swagger. Until the market gets a clear snapshot on the viability of Organovo's business and its legitimate upside and market positioning, speculators on both ends will concoct their own theories for why the stock will either change the world or fade away.

Keep an eye on Organovo, but always be aware that this tantalizing Petri dish of an investment is going to be ridiculously risky in the near term.