The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”) and include the accounts of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated. The Company has reclassified certain amounts previously reported in its consolidated financial statements to conform to the current presentation.

The Company’s operations and performance may vary based on worldwide economic and political conditions, which have been adversely impacted by continued global economic uncertainty, political instability, and military hostilities in multiple geographies, including the COVID-19 pandemic, the ongoing military conflict between Russia and Ukraine, domestic and global inflationary trends, rising interest rates, global supply shortages, and a tightening labor market. For example, the Company has experienced staff shortages at its contact centers as a result of the COVID-19 pandemic and federal, state and local responses thereto. A severe or prolonged economic downturn or period of global political instability could drive hospitals and other healthcare professionals to tighten budgets and curtail spending, which could in turn negatively impact rates at which physicians prescribe the Company’s Zio Services. In addition, higher unemployment rates or reductions in employer-provided benefits plans could result in fewer commercially insured patients, resulting in a reduction in the Company’s margins and impairing the ability of uninsured patients to make timely payments. A weak or declining economy could also strain the Company’s suppliers, possibly resulting in supply delays and disruptions. There is also a risk that one or more of the Company’s current service providers, suppliers, or other partners may not survive such difficult economic times, which could directly affect the Company’s ability to attain its goals on schedule and on budget. If the current equity and credit markets deteriorate, it may make any necessary debt or equity financing more difficult, more costly, and more dilutive. The Company cannot predict the timing, strength, or duration of an economic downturn, instability, or recovery, whether worldwide, in the United States, or within its industry.

Macroeconomic factors have contributed to delays in payments of outstanding receivables, supply chain disruptions, including shortages and inflationary pressure, uncertain or reduced demand, and the impact of any initiatives or programs that the Company has undertaken to address financial and operational challenges faced by the Company’s customers. This impact is having a material, adverse impact on liquidity, capital resources, supply chain, operations and business and those of the third parties on which the Company relies, and could worsen over time. In addition, the extent to which macroeconomic conditions, including inflation, increasing interest rates and other effects of the COVID-19 pandemic, impacts the Company’s results will depend on future developments, which are highly uncertain and cannot be predicted. The full extent of potential delays or impacts on the business, financial condition, cash flows and results of operations remains unknown.

The Company receives revenue for the Zio Services primarily from third-party payors, which include commercial payors and government agencies, such as the Centers for Medicare & Medicaid Services (“CMS”). Third-party payors require the Company to identify the service for which it is seeking reimbursement by using a Current Procedural Terminology (“CPT”) code set maintained by the American Medical Associations. These CPT codes are subject to periodic change and update, which will impact the reimbursement rates for the Company’s Zio Services.

CMS updates the reimbursement rates for diagnostic tests performed by IDTFs annually via the Medicare Physician Fee Schedule, and effective January 1, 2023, CMS established national payment rates for the CPT codes the Company uses to report the long-term Holter monitoring services it performs with its Zio XT System: CPT codes 93247 (for wear-time of greater than 7 days and up to 15 days) and 93243 (for wear-time of greater than 48 hours and up to 7 days). Based on the relative value units CMS assigned to CPT codes 93247 and 93243, the national reimbursement rates for these services in 2023 are $243.65 and $231.79, respectively, and range from $247.59 to $334.46 and $235.54 to $318.17 for the Company’s Medicare-enrolled IDTF locations in Deerfield, Illinois, Houston, Texas, and San Francisco, California, when considering the geographic practice cost index for these locations. Because remote cardiac monitoring technology, including the Zio System, are rapidly evolving, there is a continuing risk that relative value units assigned, and reimbursement rates set, by CMS may not adequately reflect the value and expense of this technology and related monitoring services, and the Company cannot provide certainty that CMS will not reduce these rates in the future, which would adversely affect the Company’s financial results.

The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the years presented. On an ongoing basis, management evaluates its estimates, including those related to revenue recognition, contractual allowances, allowance for doubtful accounts, the useful lives of property and equipment, the recoverability of long-lived assets including the estimated usage of the printed circuit board assemblies (“PCBAs”), the incremental borrowing rate for operating leases, accounting for income taxes, impairment of right-of-use ("ROU") assets, and various inputs used in estimating stock-based compensation. Actual results may differ from those estimates.

Operating segments are defined as components of an enterprise where separate financial information is evaluated regularly by the chief operating decision maker, which the Company has identified as being the chief executive officer, in deciding how to allocate resources and assessing performance. The Company operates as one operating segment. The Company's chief operating decision maker allocates resources and assesses performance at the consolidated level.

The Company's short-term investments consist primarily of commercial paper, corporate bonds, U.S. agency obligations and U.S. treasury securities. The Company typically invests in highly-rated securities, and its investment policy generally limits the amount of credit exposure to any one issuer. The Company's policy generally requires investments to be investment grade, with the primary objective of minimizing the potential risk of principal loss. The Company classifies investments as available-for-sale at the time of purchase and re-evaluates such classification as of each balance sheet date. Available-for-sale debt securities with an amortized cost basis in excess of the estimated fair value are assessed to determine what amount of that difference, if any, is caused by expected credit losses. Allowance for credit losses on available-for-debt securities are recognized as a charge in other income (expense), net on the Company's consolidated statements of operations and any remaining unrealized losses, net of taxes, are included in accumulated other comprehensive loss in accumulated deficit on the consolidated balance sheets. There were no impairment charges for any unrealized losses during the years ended December 31, 2022, 2021, and 2020.

The Company establishes an allowance for doubtful accounts for estimated uncollectible receivables based on its assessment of the collectability of customer accounts and recognizes the provision as a component of selling, general and administrative expenses. The Company records a provision for contractual allowances based on the estimated differences between contracted amounts and expected collection rates. Such provisions are based on the Company's historical experience and are reported as a reduction of revenue.

Financial instruments that potentially subject the Company to a concentration of credit risk consist primarily of cash and cash equivalents, investments and accounts receivable. Cash balances are deposited in financial institutions which, at times, may be in excess of federally insured limits. Cash equivalents are invested in highly rated money market funds. The Company invests in a variety of financial instruments, such as, but not limited to, U.S. government securities, corporate notes, commercial paper and, by policy, limits the amount of credit exposure with any one financial institution or commercial issuer. The Company has not experienced any material losses on its deposits of cash and cash equivalents or investments.

Concentrations of credit risk with respect to accounts receivable are limited due to the large number of customers comprising the Company’s customer base and their dispersion across many geographies. The Company does not require collateral. The Company records an allowance for doubtful accounts based on the assessment of the collectability of customer accounts, considering factors such as historical experience, credit quality, the age of the accounts receivable balances, and current economic conditions that may affect a customer’s ability to pay. The Centers for Medicare and Medicaid Services (“CMS”), accounted for approximately 25%, 14% and 27% of the Company’s revenue for the years ended December 31, 2022, 2021, and 2020, respectively. CMS accounted for 22% and 8% of accounts receivable as of December 31, 2022 and 2021, respectively.

The Company continuously monitors the effects of inflationary factors, such as increases in cost of goods sold and selling and operating expenses, which may adversely affect its results of operations. Specifically, the Company may experience inflationary pressure affecting freight costs, the cost of the components for the Company’s Zio Services, overhead costs relating to maintenance of the Company’s facilities, and in the wages paid to its employees due to challenging labor market conditions. Competitive and regulatory conditions may restrict the Company’s ability to fully recover these costs through price increases. As a result, it may be difficult to fully offset the impact of persistent inflation. The Company’s inability or failure to do so could have a material adverse effect on its business, financial condition and results of operations or cause the Company to need to obtain additional capital in future earlier than anticipated.

Inventory owned by the Company is valued at cost, on the first in, first out (“FIFO”) basis, or the lower of cost or net realizable value. The Company records write-downs of inventory that is obsolete or in excess of anticipated demand. The Company also records market value based write-downs in consideration of product lifecycle stage, technology trends, product development plans and assumptions about future demand and market conditions. Actual demand may differ from forecasted demand, and such differences may have a material effect on recorded inventory values. Inventory write-downs are charged to cost of revenue and establish a new cost basis for the inventory.

Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization is computed using the straight-line method over the estimated useful lives of the assets, ranging from three to five years. Leasehold improvements are amortized over the shorter of the lease term or the estimated useful lives of the assets. Maintenance and repairs are charged to expense as incurred, and improvements and betterment are capitalized.

The Company uses PCBAs in each wearable Zio XT patch, Zio AT patch and the Zio Monitor as well as the wireless gateway used in conjunction with the Zio AT patch. The PCBAs are used numerous times and have useful lives beyond one year. Each time a PCBA is used in a wearable Zio XT patch, Zio AT patch, or the Zio Monitor or a wireless gateway is used with a Zio AT patch a portion of the cost of the PCBA and/or gateway is recorded as a cost of revenue. The Company periodically evaluates and has based its estimates of how many times a PCBA can be used on testing in research and development, loss rates, product obsolescence, and the amount of time it takes the device to go through the manufacturing, shipping, customer shelf and patient wear time and upload process. The fair value of the Company's PCBAs is included in Other Assets on the Consolidated Balance Sheets.

The Company capitalizes qualified implementation costs incurred in a hosting arrangement that is a service contract for which it is the customer in accordance with the requirements for cloud computing arrangements ("CCA") to the extent it is incurred in the course of developing internal-use software. These capitalized implementation costs are generally amortized over the fixed, non-cancellable term of the associated hosting arrangement on a straight-line basis are recorded in prepaid expenses and other current assets or in other noncurrent assets. The Company amortizes capitalized implementation costs in a CCA on a straight-line basis over the terms of the associated hosting arrangement. The Company recorded an immaterial amount of amortization expense during the years ended December 31, 2022, 2021, and 2020.

Goodwill represents the excess of the purchase price of an acquired business over the fair value of the underlying net tangible and intangible assets. Goodwill amounts are not amortized, but rather tested for impairment at least annually, and more frequently when changes in circumstances indicate that the carrying value may not be recoverable. The Company has determined that it operates its business as one reporting unit and the Company completes its annual impairment test in the fourth quarter. In the event that the Company determines that the fair value of the reporting unit is less than the reporting unit's carrying value, goodwill impairment charge will be incurred for the amount of the difference during the quarter in which the determination is made. The Company did not record any goodwill impairment charges in the years ended December 31, 2022, 2021, and 2020.

The Company reviews long-lived assets for impairment annually or whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by comparing the carrying amount to the future net cash flows that the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured as the amount by which the carrying amount of the assets exceeds the projected discounted future net cash flows arising from the asset.

Any impairments to ROU assets, leasehold improvements, or other assets as a result of a sublease or other similar action are initially recognized when a decision to take such action is made and recorded as an operating expense. Similar to other long-lived assets, management tests ROU assets for impairment whenever events or changes in circumstances occur that could impact the recoverability of these assets. For ROU assets, such circumstances may include subleases that do not fully recover the costs of the associated leases or commitments to sublease a property. For the year ended December 31, 2022, the Company recorded $23.2 million of long-lived asset impairment charges in the consolidated statement of operations. In addition, see Note 7, Impairment and Restructuring Charges, included in the notes to the consolidated financial statements.

The Zio XT System is a prescription-only, remote ECG monitoring system that consists of the Zio XT patch that records the electric signal from the heart continuously for up to 14 days and the ZEUS System, which supports the capture and analysis of ECG data recorded by the Zio XT patch at the end of the wear period, including specific arrhythmia events detected by the ZEUS algorithm. The final step in the Zio Services is the delivery of an electronic Zio report to the prescribing physician with a summary of findings. The Company’s Zio XT services are generally billable when the Zio report is issued to the physician.

The Zio Monitor System is the next generation of the Zio XT System, and is a prescription-only, remote ECG monitoring system that consists of the Zio Monitor patch that records the electric signal from the heart continuously for up to 14 days and the ZEUS System, which supports the capture and analysis of ECG data recorded by the Zio Monitor patch at the end of the wear period, including specific arrhythmia events detected by the ZEUS algorithm.

The Zio AT System is a prescription-only, remote ECG monitoring system that similarly consists of the Zio AT patch that records the electric signal from the heart continuously for up to 14 days and the ZEUS System, but which also incorporates the Zio AT wireless gateway that provides connectivity between the patch and the ZEUS System during the patient wear period. The wireless gateway, slightly larger than a smart phone, is provided to the patient at the time of Zio AT patch application and collects and transmits data from the Zio AT patch to the cloud via a LTE protocol. The Zio AT service revenue is recognized over the patient wear period and delivery of electronic Zio reports with two performance obligations.

The Company recognizes as revenue the amount of consideration to which it expects to be entitled in exchange for performing the service. The consideration the Company is entitled to varies by portfolio, as further defined below, and includes estimates that require significant judgment by management. A unique aspect of healthcare is the involvement of multiple parties to the service transaction. In addition to the patient, often a third-party, for example a commercial or governmental payor or healthcare institution, will pay the Company for some or all of the service on the patient’s behalf. Separate contractual arrangements exist between the Company and third-party payors that establish amounts the third-party payor will pay on behalf of a patient for covered services rendered.

A small portion of the Company’s transactions are covered by third-party payors with whom there is neither a contractual agreement nor an established amount that the third-party payor will pay. In determining the collectability and transaction price for its service, the Company considers factors such as insurance claims which are adjudicated as allowable under the applicable policy and payment history from both payors and patient out-of-pocket costs, payor coverage, whether there is a contract between the payor or healthcare institution and the Company, historical amount received for the service, and any current developments or changes that could impact reimbursement and healthcare institution payments. Certain of these factors are forms of variable consideration which are only included in the transaction price to the extent it is probable that a significant reversal of cumulative revenue will not occur when the uncertainty associated with the variable consideration is subsequently resolved.

The Company is utilizing the portfolio approach practical expedient under ASC 606, Revenue from Contracts with Customers, whereby services provided under each of the above payor types form a separate portfolio. The Company accounts for the contracts within each portfolio as a collective group, rather than individual contracts. Based on history with these portfolios and the similar nature and characteristics of the patients within each portfolio, the Company has concluded that the financial statement effects are not materially different than if accounting for revenue on a contract-by-contract basis.

For contracted and CMS portfolios, the Company recognizes revenue, net of contractual allowances, and recognizes an allowance for doubtful accounts for uncollectible patient accounts receivable. The transaction price is determined based on negotiated rates, and the Company has historical experience of collecting substantially all of these contracted rates. These contracts also impose a number of obligations regarding billing and other matters, and the Company’s noncompliance with a material term of such contracts may result in a denial of the claim. The Company accounts for denied claims as a form of variable consideration that is included as a reduction to the transaction price recognized as revenue. The Company estimates the denied claims which require management judgment. The estimated denied claims are based on historical information and judgement includes the historical period utilized. The Company monitors the estimated denied claims against the latest available information, and subsequent changes to the estimated denied claims are recorded as an adjustment to revenue in the periods during which such changes occur. Delays in claims submissions could lead to an increase in denials if the Company misses the payors’ filing deadlines and could result in a reduction in the Company’s receipt of payments. Historical cash collection indicates that it is probable that substantially all of the transaction price, less the estimate of denied claims, will be received. Contracted payors may require that the Company bills patient co-payments and deductibles and from time to time the Company may not be able to collect such amounts due to credit risk. The Company provides for estimates of uncollectible patient accounts receivable, based upon historical experience where judgment includes the historical period utilized, at the time revenue is recognized, with such provisions presented as bad debt expense within the selling, general and administrative line item of the consolidated statement of operations. Adjustments to these estimates for actual experience are also recorded as an adjustment to bad debt expense.

As discussed in the Accounts Receivable, Allowance for Doubtful Accounts and Contractual Allowances section above, the inherent uncertainty caused by the longer collection cycle and claims adjudication process related to delays in submission because of the CPT code transition in 2021 could result in additional provisions for contractual allowances and doubtful accounts which would negatively impact the Company’s results of operations in future periods.

For healthcare institutions, the transaction price is determined based on negotiated rates, and the Company has historical experience collecting substantially all of these contracted rates. Historical cash collections indicate that it is probable that substantially all of the transaction price will be received. As such, the Company is not providing an implicit price concession but, rather, has chosen to accept the risk of default, and any subsequent uncollected amounts are recorded as bad debt expense to selling, general and administrative expense in the consolidated statements of operations.

The Company determines if an arrangement is a lease at inception. The Company's lease agreements generally contain lease and non-lease components. Payments under its lease arrangements are primarily fixed. Non-lease components primarily include payments for maintenance and utilities. The Company combines fixed payments for non-lease components with lease payments and accounts for them together as a single lease component which increases the amount of the Company’s ROU assets and lease liabilities.

ROU assets and lease liabilities are recognized at the present value of the future lease payments at the lease commencement date. The interest rate used to determine the present value of the future lease payments is the Company's incremental borrowing rate, because the interest rate implicit in its leases is not readily determinable. The Company's incremental borrowing rate is estimated to approximate the interest rate on a collateralized basis with similar terms and payments, and in economic environments where the leased asset is located. The Company's lease terms include periods under options to extend or terminate the lease when it is reasonably certain that it will exercise that option. The Company generally uses the base, non-cancelable, lease term when determining the ROU assets and lease liabilities. ROU assets are adjusted for any prepaid lease payments and lease incentives.

Cost of revenue includes direct labor, material costs, overhead, data analysis, customer care, equipment and infrastructure expenses, amortization of internal-use software, and shipping and handling. Direct labor includes payroll and personnel-related costs involved in manufacturing. Material costs include both the disposable costs of the device and amortization of the PCBAs. Each time the PCBA is used in a wearable Zio XT System, a portion of the cost of the PCBA is charged to cost of revenue.

The Company's general and administrative expenses consist primarily of personnel costs for executive, finance, legal and administrative personnel, including stock-based compensation. Other significant expenses include professional fees for legal and accounting services, consulting fees, recruiting fees, bad debt expense, third-party patient claims processing fees and travel expenses. In addition, the Company incurred transformation costs to scale its organization during the year and expect to incur additional transformation costs throughout 2023 with the restructuring activities to be substantially complete by mid-2024. Upon completion, the Company expects to achieve operational efficiencies in its administrative expenses.

The Company uses the asset and liability method to account for income taxes in accordance with the authoritative guidance for income taxes. Under this method, deferred tax assets and liabilities are determined based on future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, and tax loss and credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates applied to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance is established when necessary to reduce deferred tax assets to the amount expected to be realized.

The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that has a greater than 50% likelihood of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company records interest and penalties related to unrecognized tax benefits in income tax expense. To date, there have been no interest or penalties charged in relation to the unrecognized tax benefits.

The Company measures the estimated fair values of its restricted stock units based on the closing price of the Company's stock on the grant date. For performance-based restricted stock units, the Company estimates the fair value based on the closing price of its stock on the grant date and, if the award includes a market condition, a Monte Carlo simulation model. In addition, for performance-based restricted stock units, the Company applies a probability assessment to determine the probable achievement of the performance-based metrics.

Stock-based compensation expense is recognized over the requisite service period using the straight-line method and is based on the value of the portion of stock-based payment awards that is ultimately expected to vest. As such, the Company's stock-based compensation is reduced for the estimated forfeitures at the date of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. For restricted stock, the compensation cost for these awards is based on the closing price of the Company’s common stock on the date of grant, and recognized as compensation expense on a straight-line basis over the requisite service period.

The Company recognizes compensation expense related to the Employee Stock Purchase Plan (“ESPP”) based on the estimated fair value of the options on the date of grant, net of estimated forfeitures. The Company estimates the grant date fair value, and the resulting stock-based compensation expense, using the Black-Scholes option pricing model for each purchase period. The grant date fair value is expensed on a straight-line basis over the offering period.