(Reuters) - Cybersecurity firm Palo Alto Networks said it expects to grow sales at a double-digit pace over the next three years and forecast robust free cash flow, sending its shares up 8% in volatile after-hours trading on Wednesday.

Palo Alto’s upbeat forecast came as it reported better-than-expected fourth-quarter revenue and profit, helped by strong demand for its cloud security products.

The company said the increasing popularity of its cloud security tool Prisma Access had boosted confidence it can achieve a 20% compounded annual growth rate for billings and revenue over the three-year period.

Palo Alto competes in a tough market dominated by traditional firewall provider Cisco Systems Inc, Check Point Software Technologies and Juniper Networks Inc.

Earlier on Wednesday, the company’s shares fell as much as 10% after it forecast fiscal 2020 adjusted profit below Wall Street estimates.

Palo Alto forecast fiscal 2022 sales would hit $5 billion, against an average $4.3 billion expected by four analysts, according to IBES data from Refinitiv.

The company expects 2022 free cash flow - the cash left over after paying for operating expenses and capital expenditures - of about $4 billion, above an average estimate of $1.58 billion provided by two analysts on Refinitiv Eikon.

“Strong billings and revenue guidance, alongside affirmation that Palo Alto will not be drastically changing its selling model, which would affect free cash flow, helped qualm investor fears,” said Mark Cash, analyst with Morningstar.

The company on Wednesday acquired Zingbox, an IoT security provider, for $75 million in cash.

Earlier this year, Palo Alto bought U.S.-Israeli information security firm Demisto Inc as well as Israel-based cybersecurity firms Twistlock and PureSec. Last October, the company acquired U.S-based cloud security company Redlock.

Total revenue rose 22.4% to $805.8 million in the fourth quarter, slightly above the $802.4 million expected by analysts.

Excluding items, Palo Alto earned $1.47 per share in the quarter, beating expectations of $1.42 a share.