Maple Grove medical device maker Inspire Medical has filed for an initial public offering of stock to raise up to $86.3 million.

Inspire Medical is an 11-year-old privately held company that makes an implanted medical device to treat chronic obstructive sleep apnea with electricity. The Inspire device, which was approved by the U.S. Food and Drug Administration in 2014, monitors a sleeping person's breathing and delivers a mild current to the hypoglossal nerve to stop a person's loud snoring and snorting in bed.

The Inspire therapy is an alternative to continuous positive airway pressure (CPAP) machines, which require a user to wear a facemask at night. The therapy is said to be less invasive than other forms of surgery for the condition.

CPAP machines don't require surgery and are the mainline therapy for chronic obstructive sleep apnea (OSA). However, studies show that between one-third and two-thirds of all CPAP patients are not fully compliant with the therapy, according to Inspire Medical.

Given that an estimated 2 million Americans are prescribed CPAP machines each year, Inspire Medical said the company has an annual addressable market of about 500,000 OSA patients who can't or don't use CPAP and have an anatomy that is conducive the Inspire therapy.

Based on the number of patients and the undisclosed average selling price of the Inspire device, Inspire estimates there is an annual U.S. market opportunity of about $10 billion, according to its IPO paperwork filed with the Securities and Exchange Commission.

The device has been covered by insurance for many patients. The Inspire therapy is on the Federal Supply Schedule, which means it is available at some VA and military hospitals, and it is also covered by Medicare in some areas of the country.

As of January 2018, more than 200 private insurance companies have paid for Inspire therapies on a case-by-case, prior-authorization basis, Inspire's website said.

Last year, Inspire Medical generated almost $29 million in sales and reported a gross margin of 79 percent. But like many smaller medical device companies, it spends heavily on research and sales and marketing activities. As a result, it posted a net loss of $17.5 million last year and ended 2017 with an accumulated deficit of $125 million.

Underwriters for the offering include Bank of America Merrill Lynch, Goldman Sachs, Guggenheim Securities, Stifel and Wells Fargo Securities.

Joe Carlson • 612-673-4779