What happened

Shares of VirnetX (NYSEMKT: VHC) jumped as much as 23% today after a court rejected Apple's (NASDAQ: AAPL) efforts to overturn a previous ruling in a case that it lost. VirnetX scored a $502.8 million victory against the Mac maker last fall over allegations that Apple infringed on VirnetX's patents related to virtual private networks (VPNs). As of 12:20 p.m. EST, the stock had given up some of those gains and was up 9%.

So what

The court also granted motions for supplemental damages and ongoing royalties and interest. Last week, the federal judge also denied Apple's motion for a new trial. The two companies have been sparring in court for about a decade, as VirnetX has long argued that Apple's FaceTime and iMessage communications services infringe on its intellectual property (IP).

Image source: Getty Images.

VirnetX is often referred to as a patent troll, as it primarily develops patented technology that it seeks to license to other companies and then sues if it believes that its IP is being infringed upon.

Now what

Considering the protracted length of the legal battle, the additional interest could add up. In December, VirnetX had asked the court to add $116 million in interest to the financial penalty. On top of that, the company wants to impose an $0.84 royalty per unit on all infringing Apple devices sold going forward. Apple argues that the two patents at the heart of the case have been invalidated and that any potential royalty should be a maximum of $0.19 per unit, although it believes it should not pay any per-unit royalties.

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Evan Niu, CFA owns shares of Apple. The Motley Fool owns shares of and recommends Apple. The Motley Fool has a disclosure policy.