LifeProof CEO Gary Rayner, left, and counsel James Nolan show off the company’s wares. LifeProof has spent $10 million — including legal fees — on its line of accessories for Apple Inc. electronics. The cost of developing and protecting intellectual property is an increasingly important aspect of business.

LifeProof CEO Gary Rayner, left, and counsel James Nolan show off the company’s wares. LifeProof has spent $10 million — including legal fees — on its line of accessories for Apple Inc. electronics. The cost of developing and protecting intellectual property is an increasingly important aspect of business.

LifeProof has built a burgeoning business on the strength of a slim, protective iPhone case...