All of GT Advanced Technologies(NASDAQ: GTAT) businesses seemed to deteriorate at the same time over the last few years, and now business is picking up at the same time. A sapphire deal with Apple (AAPL 1.66%) is progressing well, solar customers are showing interest in expanding, and polysilicon has potential for growth.  

The promise GT Advanced Technologies has ahead wasn't evident in the fourth quarter, though. Revenue dropped a whopping 68% to $32.6 million, and net loss was $41.8 million, or $0.33 per share. Despite the losses, the company ended the year with $593.0 million in cash and equivalents, up from $418.1 million a year ago.  

A big reason for the increased cash balance was two prepayments from Apple, which totaled $225 million in 2013. That'll eventually become revenue, but for now, it's being used to build sapphire capacity in Apple's plant in Arizona.  

Beyond the Apple deal, there's little in the way of new business, but 2014 should be a transitional year. PV and polysilicon customers are starting to pick up orders, and management expects 85% of $600 million to $800 million of revenue to come in the second half of the year.

Both the solar and LED markets look like they're in full-on recovery mode right now, and as costs fall and demand picks up, we'll see equipment demand rise. That inflection point has been talked about for years, but it looks like it'll be a reality in late 2014 or 2015. Solar products in particular will likely see large orders as manufacturers around the world invest in the next generation of high-efficiency cell manufacturing.

Still a roll of the dice
The challenge with a stock like GT Advanced Technologies is that there's a lot of promise, but not a lot of financial results yet. Over the past year alone, the company's loss was $86.6 million, a huge figure for a company with a $1.7 billion market cap.

To live up to that valuation, we need to see product coming off the line to Apple this year and see orders from solar and LED customers pick up. Management is confident that will happen, but it's still a risky bet for investors. I like the risk/reward profile of GT Advanced Technologies, but it isn't a stock for everyone.