The Federal Circuit on Friday ordered a new trial to determine whether Inventist Inc. should receive lost profits after a jury determined Ninebot Inc. infringed its unicycle patent, saying key information was left out that could have impacted the jury's $800,000 award.

A Western District of Washington judge erred when barring Ninebot from presenting evidence that it had a non-infringing substitute product that could have competed with Inventist, a three-judge panel concluded in a nonprecedential opinion from U.S. Circuit Judge Timothy B. Dyk.

In order to collect lost profits, the patent owner has to show that it would have obtained those sales but for the infringement. The jury should have been able to decide whether Inventist would have received those sales if Ninebot had another non-infringing, electrically powered, self-balancing unicycle.

U.S. District Judge Barbara Jacobs Rothstein determined Ninebot couldn't present its argument to the jury because it had not sold the substitute product. But the Federal Circuit says its precedent allows technology that was available to count toward a substitute product, even if it wasn't sold.

The panel rejected Inventist's claim that Ninebot's substitute product would not have been ready to come to market, saying there was evidence that, "if credited by a jury, could have been sufficient to establish the existence of non-infringing substitutes, which would have defeated the lost profits claim."

The Federal Circuit upheld the jury's $29,593 reasonable royalty, even as it vacated the $835,220 in lost profits.

In other parts of the decision, the Federal Circuit upheld Judge Rothstein's ruling that a second generation of Ninebot's unicycles didn't infringe Inventist's patent.

The Federal Circuit also rejected Ninebot's claim that it should have received a new trial based on Inventist not properly marking its products with the necessary patent information, saying it didn't have jurisdiction.

The marking requirement argument was still being reviewed at the district court when Ninebot filed its notice of appeal. When Judge Rothstein rejected the argument, Ninebot never supplemented that notice, so the court could not review the question.

An attorney for Ninebot applauded the decision on Friday.

"The court's reaffirmation that accused infringers are entitled to present evidence of readily available, non-infringing alternatives is an important safeguard ensuring that damages are determined on a sound and legally supported basis," Andrew C. Aitken of Aitken Law Offices told Law360 in an email.

Counsel for Inventist didn't immediately respond to a request for comment Friday.

The patent-in-suit is U.S. Patent No. 8,807,250.

Circuit Judges Timothy B. Dyk, Todd M. Hughes and Leonard P. Stark sat on the panel for the Federal Circuit.

Inventist is represented by Devra R. Cohen and Benjamin J. Hodges of Foster Garvey PC.

Ninebot is represented by Andrew C. Aitken of Aitken Law Offices.

The case is Inventist Inc. v. Ninebot Inc. (USA), case numbers 24-1010 and 24-1267, in the U.S. Court of Appeals for the Federal Circuit.