A glance at FireEye's (NASDAQ: FEYE) second-quarter earnings may raise more questions than answers that explain why its stock has soared 50% this year. But digging a bit deeper shines a bright light on a number of areas CEO Kevin Mandia has delivered on in the past year.

Mandia made his objectives clear when he took the CEO reins in June 2016, and the strides he and the FireEye team have already made in a relatively short period of time demonstrates why its stellar performance in 2017 is warranted. FireEye is hardly out of the woods, but the light at the end of the tunnel is why its stock could be a goldmine for growth investors.

Joining the party

One of FireEye's core objectives is shifting its focus from a reliance on generating new product sales. The goal is to transition to a cloud-based software subscription model to build a stable foundation of recurring revenue, much like FireEye's peers including Check Point Software (NASDAQ: CHKP).

FireEye's $185.5 million in revenue was a surprisingly strong 6% increase year over year. Though FireEye's sales beat expectations and resulted in another stock price boost, it was the revenue mix that growth investors should focus on.

Product sales in the quarter sank 23% to $31.2 million, and are down 26% to $54.95 million in the first half of the year. That may not seem like a win, but it's in line with Mandia's focus on building a steady stream of revenue.

The decline in product sales was more than made up for by the $154.27 million in cloud software subscription revenue, good for a 15% jump compared to a year ago. A primary reason FireEye could be a gold mine for growth investors is that it will likely report similar growth where it counts -- subscriptions -- for the current quarter on Nov. 1.

There is an additional benefit to building a foundation of on-going revenue, and FireEye nailed it again last quarter: lower operating expenses, particularly sales overhead.

When less is more

FireEye was able to shave an impressive 24% off its total operating expenses last quarter, down to $178.21 million. There's still a long road ahead, but to cut overhead that dramatically in just a year is not only a significant step in the right direction, it bodes well for the future.

A particular area of focus of FireEye, and its industry peers, is cutting sales costs which will be made easier by its recurring revenue efforts. FireEye can look to Check Point as the poster child for managing sales expenses. Last quarter Check Point spent $114.68 million on sales-related overhead, equal to a meager -- relative to its competitors -- 25% of its $458.73 million in total revenue.