Shares of GT Advanced Technologies (NASDAQ: GTAT) have absolutely crushed it over the past 14 months, up more than 324%, beating the market by almost 300%. Now, get this: There is strong indication that the stock may just be undervalued today. Sounds crazy, I know, but based on what management told us just this week, the stock trades at a price to earnings of 8.4. As a comparison, partner Apple (AAPL 0.51%), largely the source of GT Advanced's first step toward massive growth through its partnership to produce Sapphire for an as-yet unnamed product, carries a P/E ratio of around 13. 

The difference? Apple's P/E of 13 is based on the past 12 months -- actual proven results -- while the P/E of 8.4 I'm touting for GT Advanced is based on the $1.50 per share in (non-GAAP) earnings that management is telling us the company will reach... in 2016. Obviously there's a lot of time -- and work -- before the company actually gets to that point, but any way you slice it, today's share price looks awfully attractive based on that kind of potential. Let's take a look at how GT Advanced will get there. 

Hyperion is one of GT's technologies in development that have huge potential. Source: GT Advanced.

Looking beyond Sapphire and Apple, to new and old markets
CEO Tom Gutierrez has been telling us for several years that the company would invest in technologies like Sapphire in efforts to both diversify the business away from its then-core PV and polysilicon businesses, and to leverage its technologies in new markets. While the solar business was getting killed during 2011 and 2012, GT Advanced continued to invest in its ASF technology, which, at the time, was less than one-third of total sales. Even in 2013, Sapphire only represented 16% of the company's total sales, versus 30% in 2012. This was largely the result of the deal with Apple, of course, as the company essentially quit taking orders for new ASF equipment, instead diverting all of its manufacturing capacity to building furnaces for its Arizona plant, which will supply Apple alone. Additionally, the company made the decision to update its other facility on the east coast as well. 

SiC (Silicon Carbide) offers enormous potential in powering electronics devices. Source: GT Advanced.

The result was -- as management told us -- almost no new sales in this category, even as its core PV and polysilicon business continue to struggle. However, managment is giving us another indication -- as it did with the Sapphire business a couple of years ago -- that the company would continue to develop new technologies and expand into new areas. Gutierrez, from Monday's earnings call:

...our entry into the Sapphire materials business may enable us to expand into other material segments, once we have fully ramped the operation in Arizona. In addition, many of the diversification and investment seeds that we have planted over the last several years in the LED, power electronics, advanced solar, and industrial markets, are expected to begin to bear fruit over the next 18 months.

Sapphire material as it appears after being grown in ASF. Source: GT Advanced.

So, even as the new deal with Apple unfolds and gradually adds powerful cash-flow and earnings over the next couple of years, GT Advanced isn't resting on its laurels. The company is pushing ahead to leverage its materials know-how into new markets. Management is also refocusing on PV and polysilicon as solar manufacturers -- key customers for GT Advanced -- start investing in additional capacity and capability. 

Final thoughts: The future is brighter than solar and shinier than Sapphire 
Investors need to remember that the stock price is still below its 2008 IPO price, and the all-time high set in 2011. Before selling just based on strong returns over the past year, it's important to remember that investing in a company is largely about what's coming, not what has already happened. GT Advanced's CEO -- who's set very reasonable expectations in the past -- is telling us that today's stock price equates to an incredible bargain based on what the company could be earning in just two years' time. 

For me, that means holding on tight to my shares. Think I'm wrong? Tell me why in the comments below.