What happened 

Shares of fuel cell manufacturer Ballard Power Systems Inc. (BLDP -2.68%) fell as much as 15.5% in trading Thursday after the company reported a fourth-quarter loss. Shares were still down 12.6% as of 3:05 p.m. EST. 

So what

Revenue jumped 31% versus a year ago to $40.3 million, and gross margin increased 100 basis points to 31% of sales, or $12.6 million. But the company still lot $2.9 million, or $0.01 per share on an adjusted basis. Analysts were expecting revenue of $34.4 million and a loss of a penny per share. 

H2 symbol made of leaves on a floor.

Image source: Getty Images.

What shocked investors today is that management said revenue would be "relatively flat in 2018," or around the $121.3 million generated in 2017. That's well below the $131.4 million analysts had estimated for the year, and investors are concerned the growth story has a few holes in it. 

Now what

Management went to great lengths to point out that uncertainty and timing were playing a role in the conservative outlook comments, so there's certainly upside for operations. What I think is more important than the murky guidance is that Ballard has $91.4 million in secured orders, and there is potential for more as California and China ramp up their demand. I actually saw fourth-quarter results as a positive for the company long-term and think this is the best-positioned fuel cell stock on the market