Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-2 of the Exchange Act.

This Quarterly Report on Form 10-Q contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. We intend such forward-looking statements to be covered by the safe harbor provisions for forward-looking statements contained in Section 27A of the Securities Act of 1933, as amended (the "Securities Act") and Section 21E of the Securities Exchange Act of 1934, as amended (the "Exchange Act"). All statements other than statements of historical facts contained in this Quarterly Report are forward-looking statements, including statements regarding our future results of operations and financial position, business strategy, the impact of the ongoing and global COVID-19 pandemic on our business, financial results and financial position, prospective products, international product approvals and commercializations, our expectations regarding the new American Medical Association reimbursement codes, our expectations regarding the final reimbursement levels for Inspire therapy procedures, research and development costs, timing and likelihood of success, other insurance providers' plans to begin approving our Inspire therapy, and the plans and objectives of management for future operations.

In some cases, you can identify forward-looking statements by terms such as ‘‘may,’’ ‘‘will,’’ ‘‘should,’’ ‘‘expect,’’ ‘‘plan,’’ ‘‘anticipate,’’ ‘‘could,’’ ‘‘intend,’’ ‘‘target,’’ ‘‘project,’’ ‘‘contemplate,’’ ‘‘believe,’’ ‘‘estimate,’’ ‘‘predict,’’ ‘‘potential’’ or ‘‘continue’’ or the negative of these terms or other similar expressions, although not all forward-looking statements contain these words. The forward-looking statements in this Quarterly Report are only predictions and are based largely on our current expectations and projections about future events and financial trends that we believe may affect our business, financial condition, and results of operations. These forward-looking statements speak only as of the date of this Quarterly Report and are subject to a number of known and unknown risks, uncertainties, and assumptions, including, but not limited to:

Moreover, we operate in an evolving environment. New risk factors and uncertainties may emerge from time to time, and it is not possible for management to predict all risk factors and uncertainties.

You should read this Quarterly Report and the documents that we reference in this Quarterly Report completely and with the understanding that our actual future results may be materially different from what we expect. We qualify all of our forward-looking statements by these cautionary statements. Except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise.

Unless the context requires otherwise, references to “Inspire,” the “Company,” “we,” “us,” and “our,” refer to Inspire Medical Systems, Inc.

Inspire Medical Systems, Inc. is a medical technology company focused on the development and commercialization of innovative, and minimally invasive solutions for patients with obstructive sleep apnea ("OSA"). Our proprietary Inspire system is the first and only United States ("U.S.") Food and Drug Administration ("FDA") approved neurostimulation technology that provides a safe and effective treatment for moderate to severe OSA. Inspire therapy received premarket approval ("PMA") from the FDA in April 2014 and has been commercially available in certain European markets since November 2011. Japan's Ministry of Health, Labour and Welfare ("MLHW") approved Inspire therapy to treat moderate to severe OSA in June 2018 and was formally added to the Japan National Health Insurance Payment Listing in June 2021. In August 2020, the Australian Therapeutic Goods Administration approved Inspire therapy to treat moderate to severe OSA, and we are currently seeking reimbursement coverage in Australia.

The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United StatesU.S. (“GAAP”) for interim financial reporting and as required by the rules and regulations of the Securities and Exchange Commission (“SEC”). Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments (including those which are normal and recurring) considered necessary for a fair presentation of the interim financial information have been included. When preparing financial statements in conformity with GAAP, we must make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues, expenses, and related disclosures at the date of the financial statements. Actual results could differ from those estimates. Additionally, the results of operations for the interim periods are not necessarily indicative of the operating results for the full fiscal year or any future periods. For a complete discussion of our significant accounting policies and other information, the unaudited financial statements and notes thereto should be read in conjunction with the audited financial statements included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2020.

We consider all highly liquid securities, readily convertible to cash, that mature withinhave original maturities of 90 days or less from the date of purchase to be cash equivalents. The carrying amount reported in the balance sheets for cash is cost, which approximates fair value.

Sales and expenses denominated in foreign currencies are translated at average exchange rates in effect throughout the year. Foreign currency transaction gains and losses are included in other expense, (income), net, in the statements of operations and comprehensive loss. Assets and liabilities of foreign operations are remeasured at period-end exchange rates with the impacts of foreign currency remeasurement recognized in other expense, (income), net in the statements of operations and comprehensive loss.

At both March 31, 2022 and December 31, 2020,2021, our short-term investments consisted of commercial paper, corporate bonds, and U.S. government securities, which are classified as available-for-sale and had maturities less than one year. Our long-term investments at September 30, 2021 consisted of U.S. government securities. Investments are reported at their estimated fair market values which are based on quoted, active or inactive market prices when available. Any unrealized gains and losses due to interest rate fluctuations and other external factors are reported as a separate component of accumulated other comprehensive (loss) income.loss. We had less than$0.2 million and $0.1 million of unrecognized loss in accumulated other comprehensive (loss) incomeloss at September 30, 2021March 31, 2022 and less than $0.1 million

December 31, 2020.2021, respectively. Any realized gains and losses are calculated on the specific identification method and reported net in other expense, (income), net in the statements of operations and comprehensive loss. For both of the three months ended September 30,March 31, 2022 and 2021, and 2020, we recognized $0 of realized gains, net. For the nine months ended September 30, 2021 and 2020, we recognized $0 and $0.1 million of realized gains, net, respectively.

We reassess our estimated credit losses on investments each reporting period. U.S. government securities and cash equivalents are under a "zero-loss exception" for credit losses, meaning no credit loss risk calculation is necessary on those instruments due to the exceptionally low rate of default, which continues to decrease as the securities approach maturity, which for us is no longer than two years. For non-U.S. government securities, we use a discounted cash flow approach to calculate expected credit losses using estimated default rates based upon historical loss data, current conditions, as well as expectations of future economic conditions. We record changes in the allowance for credit losses for available-for-sale debt securities with a corresponding adjustment in credit loss expense on the statement of operations and comprehensive loss. No reversal of a previously recorded allowance for credit losses may be made to an amount below zero. The total allowance for credit losses was $0 at both September 30, 2021March 31, 2022 and December 31, 2020.2021.

We measure certain financial assets and liabilities at fair value on a recurring basis, including cash equivalents and investments. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. A three-tier fair value hierarchy is established as a basis for considering such assumptions and for inputs used in the valuation methodologies in measuring fair value:

We use the methods and assumptions described below in determining the fair value of our financial instruments.

There were no transfers between levels during the periods ended September 30, 2021March 31, 2022 and December 31, 2020.2021.

Financial instruments, which potentially subject us to concentrations of credit risk, consist principally of cash equivalents, investments, and accounts receivable.

Our investment policy limits investments to certain types of debt securities issued by the U.S. government and its agencies, corporations with investment-grade credit ratings, or commercial paper and money market funds issued by the highest quality financial and non-financial companies. We place restrictions on maturities and concentration

We believe that the credit risk in our accounts receivable is mitigated by our credit evaluation process, relatively short collection terms, and dispersion of our customer base. We generally do not require collateral, and losses on accounts receivable have historically not been within management's expectations.significant.

Trade accounts receivable are recorded at the invoiced amount and do not bear interest. Customer credit terms are established prior to shipment with the general standard being net 30 days. Collateral or any other security to support payment of these receivables generally is not required.

Each reporting period, we estimate the credit loss related to accounts receivable based on a migration analysis of accounts grouped by individual receivables delinquency status, and apply our historic loss rate adjusted for management's assumption of future market conditions. Any change in the allowance subsequent to the effective date of January 1, 2020 from new receivables acquired, or changes due to credit deterioration on previously existing receivables, is recorded in selling, general and administrative expenses. Write-offs of receivables considered uncollectible are deducted from the allowance. Specific accounts receivable are written-off once a determination is made that the amount is uncollectible. The write-off is recorded in the period in which the account receivable is deemed uncollectible. Recoveries are recognized when received and as a direct credit to earnings or as a reduction to the allowance for credit losses (which would indirectly reduce the loss by decreasing bad debt expense).

Long-lived assets consist primarily of property and equipment and operating lease right-of-use asset and are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an

asset may not be recoverable. If circumstances require that an asset be tested for possible impairment, we compare the undiscounted cash flows expected to be generated by the asset to the carrying amount of the asset. If the carrying amount of the asset is not recoverable on an undiscounted cash flow basis, we determine the fair value of the asset and recognize an impairment loss to the extent the carrying amount of the asset exceeds its fair value. We determine fair value using the income approach based on the present value of expected future cash flows or other appropriate measures of estimated fair value. Our cash flow assumptions consider historical and forecasted revenue and operating costs and other relevant factors. We did not record any impairment charges on long-lived assets during either of the ninethree months ended September 30, 2021March 31, 2022 or 2020.2021.

Revenue is measured as the amount of consideration we expect to receive, adjusted for any applicable estimates of variable consideration and other factors affecting the transaction price, which is based on the invoiced price, in exchange for transferring products. All revenue is recognized when we satisfy our performance obligations under the contract. The majority of our contracts have a single performance obligation and are short term in nature.

Sales taxes and value added taxes in foreign jurisdictions that are collected from customers and remitted to governmental authorities are accounted for on a net basis and therefore are excluded from net sales. Shipping and handling costs associated with outbound freight after control over a product has transferred to a customer are accounted for as a fulfillment cost and are included in cost of goods sold.

Variable consideration related to certain customer sales incentives is estimated based on the amounts expected to be paid based on the agreement with the customer using probability assessments.

We offer customers a limited right of return for our product in case of non-conformity or performance issues. We estimate the amount of our product sales that may be returned by our customers based on historical sales and returns. As our historical product returns to date have been immaterial, we have not recorded a reduction in revenue related to variable consideration for product returns.

See Note 9 for disaggregated revenue by geographic area.

Cost of goods sold consists primarily of acquisition costs for the components of the Inspire system, overhead costs, scrap and inventory obsolescence, warranty replacement costs, as well as distribution-related expenses such as logistics and shipping costs, net of shipping costs charged to customers. The overhead costs include the cost of material procurement, depreciation expense for production equipment, and operations supervision and management personnel, including employee compensation, stock-based compensation, supplies, and travel.

Research and development expenses consist primarily of product development, clinical and regulatory affairs, quality assurance, consulting services, and other costs associated with products and technologies in development. These expenses include employee compensation, including stock-based compensation, supplies, materials, consulting, and travel expenses related to research and development programs. Clinical expenses include clinical trial design, clinical site reimbursement, data management, travel expenses, and the cost of manufacturing products for clinical trials.

The Black-Scholes option pricing model requires the input of certain subjective assumptions, including (i) the expected share price volatility, (ii) the expected term of the award, (iii) the risk-free interest rate and (iv) the expected dividend yield. Due to our limited operating history and a lack of company specific historical and implied volatility data, we have incorporated our historical stock trading volatility with those of a peer group of public companies for the calculation of volatility. The group of peer companies have characteristics similar to us, including stage of product development and focus on the life science industry. The historical volatilityStock-based compensation expense is calculated based on a period of time commensurate with the expected term assumption. We use the simplified method, which is the average of the final vesting tranche date and the contractual term, to calculate the expected term for options granted to employees and directors as we do not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term. The risk-free interest rate is based on a U.S. government Treasury instrument whose term is consistent with the expected term of the stock options. We use an assumed dividend yield of zero as we have never paid dividends and have no current plans to pay any dividends on our common stock.

We expense the costs of advertising, including promotional expenses, as incurred. Advertising expenses were $13.4$15.5 million and $6.8$9.0 million during the three months ended September 30,March 31, 2022 and 2021, respectively.

Operating leases are included in operating lease right-of-use ("ROU") asset, accrued expenses, and operating lease liability – non-current portion in our balance sheets. ROU assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. In determining the present value of lease payments, we use our incremental borrowing rate based on the information available at the lease commencement date as the rate implicit in the lease is not readily determinable. The determination of our incremental borrowing rate requires management judgment based on information available at lease commencement. The operating lease ROU assets also include adjustments for prepayments, accrued lease payments, and exclude lease incentives. Our lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise such options. Operating lease cost is recognized on a straight-line basis over the expected lease term. Lease agreements entered into after the adoption of ASC 842 that include lease and non-lease components are accounted for as a single lease component. Lease agreements with a noncancelable term of less than 12 months are not recorded on our balance sheets.

We account for income taxes using the liability method. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates that will be in effect when the differences are expected to reverse. Valuation allowances against deferred tax assets are established, when necessary, to reduce deferred tax assets to the amounts expected to be realized. As we have historically incurred operating losses, we have recorded a full valuation allowance against our net deferred tax assets, and there is no provision for income taxes other than

Comprehensive loss consists of net loss and changes in unrealized gains and losses due to interest rate fluctuations and other external factors on investments classified as available-for-sale. Accumulated other comprehensive (loss) incomeloss is presented in the accompanying balance sheets as a component of stockholders' equity.

Basic net loss per share is computed by dividing the net loss by the weighted average number of shares of common stock outstanding during the period. Diluted net loss per share is computed by dividing the net loss by the weighted average number of shares of common stock and dilutive potential shares of common stock outstanding during the period. Because we have reported a net loss for all periods presented, diluted net loss per share is the same as basic net loss per share as all potentially dilutive shares consisting of outstanding stock options, unvested RSUs and PSUs, and shares issuable under our employee stock purchase plan were antidilutive in those periods.

We have reviewed and considered all recent accounting pronouncements that have not yet been adopted and believe there are none that could potentially have a material impact on our business practices, financial condition, results of operations, or disclosures.

As of September 30, 2021March 31, 2022 and December 31, 2020,2021, we had no investments with a contractual maturity of greater than two years. Currently, we do not intend to sell the investments and it is not more likely than not that we will be required to sell the investments before recovery of their amortized cost bases, which may be maturity. We do not consider those investments to be other-than-temporarily impaired as of September 30, 2021.March 31, 2022. At the end of each reporting period, we evaluate potential credit impairment on available-for-sale securities in an unrealized loss

In September 2018, we entered into a non-cancelable operatingWe lease agreement to sublease approximately 45,00070,000 square feet of office space for our corporate headquarters which included real estate taxes and operating expenses in the base rent. This lease commenced January 15, 2019 and expired November 30, 2020.

Beginning December 1, 2020, inIn addition to base rent, we also pay our proportionate share of the operating expenses, as defined in the lease.leases. These payments are made monthly and adjusted annually to reflect actual charges incurred for operating expenses, such as common area maintenance, taxes, and insurance. In conjunction with this lease,the leases, the landlord agreed to provide a $0.6 milliontotal rent abatement and a refurbishment allowance in the amount of the cost of any leasehold improvements, not to exceed approximately $1.1 million upon Inspire providing the necessary documentation evidencing the costs of the leasehold improvements that are completed by May 31, 2022. However, the lease allows us to allocate the refurbishment allowance against base rent instead of taking a tenant improvement reimbursement. At this time, we intend to allocate the full amount of the refurbishment allowance against base rent.