FireEye (NASDAQ: FEYE) was once a high-growth darling in the cybersecurity sector, but the threat prevention firm's growth decelerated as the competition intensified and the stock now trades below its IPO price of $20 per share.

FireEye's stock has been stuck in neutral over the past 12 months, and investors might be wondering if it will ever rally. Let's take a closer look at FireEye's business to find out.

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What does FireEye do?

FireEye offers threat prevention solutions that intercept attacks before they breach a network. Over the past two years, FireEye pivoted away from selling on-site appliances toward cloud-based services.

This caused its revenue growth to slow down, since installing appliances generated higher initial revenues. However, FireEye hoped that shifting its focus toward cloud services would provide it with more consistent growth through subscriptions. It also believed that bundling multiple threat prevention products into a single unified platform, called Helix, would lock in its customers and widen its moat.

Under Kevin Mandia, who became CEO in 2016, FireEye focused on cutting back its operating expenses, which produced its first quarter of break-even non-GAAP earnings per share last quarter. However, FireEye remains unprofitable on a GAAP basis, mostly due to stock-based compensation (SBC) expenses, which gobbled up 23% of its revenues last quarter.

Who are FireEye's main competitors?

FireEye faces a long list of competitors, but its most prominent rivals are Palo Alto Networks (NYSE: PANW), Fortinet (NASDAQ: FTNT), and Cisco (NASDAQ: CSCO).

Palo Alto and Fortinet both offer next-gen firewalls, which allow them to cross-sell additional security products. Cisco bundles a growing list of security products with its networking hardware and software, and its portfolio includes similar threat prevention products from Sourcefire and ThreatGrid.

Image source: Getty Images.

FireEye's total revenues rose just 5% to $751 million last year, but analysts anticipate 10% growth this year as its expands its Helix, email, and endpoint protection services.

However, Wall Street expects Palo Alto's sales to grow 28% to $2.25 billion this year, and for Fortinet's sales to rise 19% to $1.78 billion. Cisco's security revenues rose 9% to $2.35 billion last year.

Therefore, FireEye generates less revenue than its rivals, and is growing at a slower rate. That makes FireEye seem like a less appealing investment -- but its stock also trades at a much lower price-to-sales ratio than the stocks of those larger companies.