What: Natural gas engine technology expert Westport Innovations(NASDAQ:WPRT) stock started the trading day off with a stumble, falling more than 10% before getting its feet back underneath it. As of this writing, shares are trading down about 7%. 

So what: The big news driving the company's stock down today was a much bigger-than-expected net loss in the third quarter, reported after market close on Nov. 10. Westport reported a net loss of $37.4 million, or about $0.58 per share, significantly wider than Wall Street estimates. However, the biggest driver of that net loss was a goodwill impairment of $18.7 million related to the company's Italian subsidiary. 

And while a goodwill impairment isn't a good thing per se, since it represents the devaluation of part of the company's business, it's a non-cash item. Some might say it's a distinction without a difference, but right now, it's a big deal for Westport because of the company's ongoing cash burn rate. 

Now what: There remains huge uncertainty and risk with Westport Innovations. The company has roughly $70 million in cash and long-term investments on hand, having burned through about $20 million in working capital in the third quarter, giving it about a year's worth of capital at the current rate. The company is also moving forward on some non-core asset sales, and expects to net roughly $50 million in proceeds from those sales, with much of that before year-end. 

Then there's the pending merger with Fuel Systems Solutions, Inc (UNKNOWN:FSYS.DL), which will bring some cash to the table, but is also a cash-burning operation as things currently stand. 

Most estimates expect that 2016 will be a tough year for selling natural gas vehicles, which doesn't bode well for Westport's or Fuel Systems' core businesses of supplying components to OEMs to make natural gas-powered vehicles. However, Westport's HPDI 2.0 program for heavy-duty engines for heavy trucking is progressing through development with a number of major OEMs, which means the company will continue to get development payments even before the program reaches commercial status, hopefully in the second half of 2016.

Furthermore, the company's joint venture with diesel engine maker Cummins, Cummins Westport, continues to do well, and will begin selling a low-NOx 9-liter engine in 2016, which is expected to be a big seller. 

Put it all together, and even with the high risk, some opportunity remains. I don't know that I'd be a buyer right now, but I plan to hold on to the shares that I own for now. Looking for deeper insight? Stay tuned for a deeper dive into Westport's full earnings report in the near future.