The accompanying financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America, or U.S. GAAP, and applicable rules and regulations of the Securities and Exchange Commission, or SEC, regarding interim financial reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by GAAP have been condensed or omitted, and accordingly the balance sheet as of December 31, 2020, and related disclosures, have been derived from the audited consolidated financial statements at that date but do not include all of the information required by GAAP for complete consolidated financial statements. These unaudited condensed consolidated financial statements have been prepared on the same basis as the Company’s annual consolidated financial statements and, in the opinion of management, reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for the fair statement of the Company’s condensed consolidated financial information. The results of operations for the three months ended March 31, 2021 are not necessarily indicative of the results to be expected for the year ending December 31, 2021, or for any other interim period or for any other future year.

The accompanying interim unaudited condensed consolidated financial statements and related financial information should be read in conjunction with the audited financial statements and the related notes thereto for the year ended December 31, 2020, included in the Company’s annual report on Form 10-K, filed with the SEC on February 26, 2021.

As a result of the COVID-19 pandemic, the Company has experienced significant business disruptions, restrictions on its ability to travel, reduction in access to customers due to diverted resources at hospitals, and shortened business hours as governments institute prolonged shelter-in-place and/or self-quarantine mandates.

Governmental mandates related to the COVID-19 pandemic have impacted, and is expected to continue to impact, Company personnel and personnel at third-party manufacturing facilities in the United States and other countries, and the availability or cost of materials, which could disrupt our supply chain and reduce margins. For instance, on or about March 16, 2020, the Health Officers of the counties of San Francisco (where the Company's headquarters is located), Santa Clara, San Mateo, Marin, Contra Costa and Alameda, where many employees are located, issued mandatory shelter-in-place orders and all employees transitioned to a remote work environment. The Company is also subject to orders in Southern California that temporarily shut down its manufacturing and distribution facilities in Cypress, California. For a limited number of employees who continue to support essential operations, including those at our manufacturing facilities, the Company has instituted protective equipment policies and, to the degree practical, social distancing measures to protect the safety of its employees. While the Company has continued to deliver its Zio service by operating with remote employees and essential employees on site, an extended implementation of these governmental mandates could further impact the Company's ability to effectively provide its Zio service, and could impede progress of all ongoing initiatives. Appropriate social distancing techniques and other

While hospital systems and healthcare facilities shift their focus and resources to treating COVID-19 patients and combating the spread of the coronavirus, the Company has adapted its service to meet the immediate needs of physicians, customers, and patients and significantly increased the utilization of its home enrollment service which allows patients to receive and wear the single-use Zio device without going to a healthcare facility.

Given the disruption in demand and an uncertain length of time to recovery, the Company adjusted its operating plan in the second quarter of 2020 by taking steps to reduce operating spend. These steps included eliminating or delaying spending on non-essential programs, reducing spend on travel and consulting, implementing a hiring freeze, furloughing approximately 5% of employees, conducting a layoff of approximately 2% of employees and implementing temporary pay reductions for our salaried workforce. From May 2020 to July 2020, the Company’s Chief Executive Officer, other named executive officers and other senior executives agreed to temporary base salary reductions and the Board of Directors agreed to a reduction in its fees until business and economic conditions improve. The Company also increased it’s bad debt reserve in anticipation of a potential increase in uncollectible co-payments from patients using the Zio Service. In August 2020, the Company reinstated furloughed employees, removed pay reductions for its salaried employees, and resumed hiring for most positions.

During the second half of 2020, the Company saw recovery of patient registrations for the Zio service to pre-COVID levels of the first quarter of 2020 and during the three months ended March 31, 2021, the Company experienced increasing levels in the Zio service patient registrations. However, this may be due, in some part, to the re-opening of certain regions within the United States and may not represent sustainable levels of patient registrations in future time periods.

The Company is continuously reviewing its liquidity and anticipated capital requirements in light of the significant uncertainty created by the COVID-19 pandemic. The Company believes it will have adequate liquidity over the next 12 months to operate its business and to meet its cash requirements. As of March 31, 2021, the Company is in compliance with its financial covenants in its debt agreement.

On March 27, 2020, as a result of the COVID-19 pandemic, Congress enacted the Coronavirus Aid, Relief, and Economic Security Act (the "CARES Act") to support businesses during the COVID-19 pandemic, including deferment of the employer portion of certain payroll taxes, refundable payroll tax credits, and technical amendments to tax depreciation methods for qualified improvement property. The primary provisions of the CARES Act which are potentially applicable to us include:

The ultimate impact of the COVID-19 pandemic is highly uncertain and subject to change. This impact is having a material, adverse impact on liquidity, capital resources, operations and business and those of the third parties on which the Company relies, and could worsen over time. The extent to which the COVID-19 pandemic impacts the Company’s results will depend on future developments, which are highly uncertain and cannot be predicted, including new information which may emerge concerning the severity of the COVID-19 pandemic and the actions to contain the COVID-19 pandemic or treat its impact, among others. The full extent of potential delays or impacts on the business, financial condition, cash flows and results of operations remains unknown. Additionally, while the potential economic impact brought by, and the duration of, the COVID-19 pandemic is difficult to assess or predict, the COVID-19 pandemic has resulted in, and may continue to result in, significant disruption of global financial markets, reducing the Company’s ability to raise additional capital through equity, equity-linked or debt financings, which could negatively impact short-term and long-term liquidity and the ability to operate on a timely basis, or at all.

Furthermore, capital markets and economies worldwide have been negatively impacted by the COVID-19 pandemic, which may result in a period of regional, national, and global economic slowdown or regional, national, or global recessions that could curtail or delay demand for the Zio service as well as increase the risk of customer defaults or delays in payments. COVID-19

Government payors may change their coverage and reimbursement policies, as well as payment amounts, in a way that would prevent or limit reimbursement for the Zio service, which would significantly harm the Company. Government and other third-party payors require the Company to report the service for which it is seeking reimbursement by using a Current Procedural Terminology (“CPT”) code-set maintained by the American Medical Association (“AMA”). For Zio XT, the Company had historically utilized temporary CPT codes (or Category III CPT codes) used for newly introduced technologies and specific to our category of diagnostic monitoring. The process to convert Category III CPT codes to Category I CPT codes is governed by the AMA and Centers for Medicare and Medicaid (“CMS”). On October 25, 2019, the AMA’s CPT Editorial Panel established two new Category I CPT codes which are applicable to the Zio service and took effect on January 1, 2021. In August 2020, CMS published the Calendar Year 2021 Medicare Physician Fee Schedule Proposed Rule which proposed reimbursement for the Category I CPT codes that were higher than their associated Category III CPT codes. Following a comment period through October 2020, CMS published its Calendar Year 2021 Medicare Physician Fee Schedule Final Rule (the “Final Rule”) in December 2020. In the Final Rule, CMS chose not to finalize national pricing for four of the eight Category I CPT codes, 93241, 93243, 93245 and 93247 which include the CPT codes that the Company will primarily use to seek reimbursement for Zio XT.

Determinations of which products or services will be reimbursed under Medicare can be developed at the national level through a national coverage determination (“NCD”) by CMS, or at the local level through a local coverage determination (“LCD”), by one or more of the regional Medicare Administrative Contractors (“MACs”) who are private contractors that process and pay claims on behalf of CMS for different regions. In the absence of a specific NCD, as is the case with Zio XT historically and for Calendar Year 2021 following the Final Rule, the MAC with jurisdiction over a specific geographic region will have the discretion to make an LCD. The Company is seeking to establish LCD pricing with one or more MACs to establish pricing for 2021 and will be subject to LCD pricing until such time CMS establishes a NCD.

On January 29, 2021, Novitas Solutions, the MAC which covers the region where the Company's Independent Diagnostic Testing Facility (“IDTF”) in Houston, Texas is located and where almost all Medicare services for Zio XT are processed, published rates for 2021 that were significantly below our historical Medicare rates for Zio XT. The Company believes that the published rates by Novitas on January 29, 2021, are based off of rates from CPT codes 93224 and 93226, which are existing CPT codes for external continuous electrocardiographic recording up to 48 hours, while the Zio service is capable of continuous monitoring for up to 14 days.

On April 10, 2021, Novitas published updated reimbursement rates for codes 93243 and 93247 at $103 and $115, respectively. The updated rates are retroactive to January 1, 2021 and replace rates initially published on January 29, 2021. The Company has accounted for this announcement as a recognized subsequent event and reflected the impact of this announcement in its condensed consolidated financial statements for the three months ended March 31, 2021. While these new rates represent an increase from the rates posted on January 29, 2021, the Company believes these rates do not appropriately reflect the clinical and economic value that long-term continuous ECG monitoring offers patients, their care teams and the Medicare system. Due to the cost of providing the service relative to the updated rates published by Novitas, the Company will not be able to provide the Zio service to the Medicare fee for service segment if these rates remain unchanged. However, the Company believes there are potential paths to more equitable rates which it plans to explore before making any changes to the availability of Zio XT in the Medicare portion of its business. It is the Company's strong preference that continued access to Zio XT is available to all patients.

The Company is currently holding a majority of Zio XT claims due to the CPT code transition. Claims are being held due to a combination of negotiations with payors and administrative delays with payors. The Company expects the level of held claims to remain high through the end of the second quarter of 2021. The high level of held claims has delayed most first quarter 2021 cash flows into the second quarter of 2021 or potentially beyond, and may impact the timing and accounting for various income statement items, particularly revenue recognition and bad debt expense. The Company has adequate balance sheet liquidity to manage through these delays in cash flow timing.

If the published rates by Novitas remain unchanged or are not significantly improved for the CPT codes listed above, thereby allowing the Company to obtain adequate Medicare reimbursement for the Zio service in the future, the Company may be unable to provide the Zio service or would experience a significant loss of revenue, either of which would have a material adverse effect on our cash flows, results of operations and financial condition.

Further, a reduction in coverage by Medicare could cause some commercial third-party payors to implement similar reductions in their coverage or level of reimbursement of the Zio service. Given the evolving nature of the healthcare industry and on-going healthcare cost reforms, the Company will continue to be subject to changes in the level of Medicare coverage for its products, and unfavorable coverage determinations at the national or local level could adversely affect its results of operations. Although a large majority of commercial customers have re-contracted the Zio XT service since the establishment of the Category I codes on January 1, 2021 matching to pre-existing rates, if the Company is unsuccessful in improving the Medicare rates before calendar year 2022, it is prudent to expect that commercial rates may begin to be more negatively impacted next year. If published rates by Novitas are not increased to above the cost of revenue for the Zio service, and the Company is unable to achieve a level of revenues adequate to support its cost structure, this would raise substantial doubts about the Company's ability to continue as a going concern.

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 reporting period. 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, and various inputs used in estimating stock-based compensation. Certain of these estimates are impacted by uncertainties surrounding COVID-19 such as revenue recognition, contractual allowances for revenue, allowance for doubtful accounts, and stock based compensation. The Company bases these estimates on historical and anticipated results, trends, and various other assumptions that management believes are reasonable under the circumstances, including assumptions as to future events. Actual results may differ from those estimates.

Short-term investments consist of debt securities classified as available-for-sale and have maturities greater than 90 days, but less than one year as of the balance sheet date. Long-term investments have maturities greater than one year as of the balance sheet date. All investments are carried at fair value based upon quoted market prices.

The Company periodically assesses its portfolio of debt investments for impairment. For debt securities in an unrealized loss position, this assessment first takes into account the intent to sell, or whether it is more likely than not that the Company will be required to sell the security before recovery of its amortized cost basis. If either of these criteria are met, the debt security’s amortized cost basis is written down to fair value through interest and other, net. For debt securities in an unrealized loss position that do not meet the aforementioned criteria, the Company assesses whether the decline in fair value has resulted from credit losses or other factors.

The Company evaluates expected credit losses by considering factors such as historical experience, market data, issuer-specific factors, and current economic conditions. Expected credit losses on available-for-sale debt securities are recognized in other income, net in the condensed consolidated statements of operations, and any remaining unrealized losses, net of taxes, are reported as a component of accumulated other comprehensive loss. The Company did not recognize any credit losses on its available-for-sale securities during the three months ended March 31, 2021 and there were no impairment charges for unrealized losses in the periods presented.

Accounts receivable includes amounts due to the Company from healthcare institutions, third-party payors, and government payors and their related patients, as a result of the Company's normal business activities. Accounts receivable is reported on the consolidated balance sheets net of an estimated allowance for doubtful accounts and contractual allowances.


	Three Months Ended March 31, 2021		Year Ended December 31, 2020		Three Months Ended March 31, 2020
Balance, beginning of period	$	12,711	$	9,049	$	9,049
Add: provision for doubtful accounts	3,095		10,515		4,592
Add: adoption of ASC 326	—		461		461
Less: write-offs, net of recoveries and other adjustments	(3,046)		(7,314)		(2,262)
Balance, end of period	$	12,760	$	12,711	$	11,840


	Three Months Ended March 31, 2021		Year Ended December 31, 2020		Three Months Ended March 31, 2020
Balance, beginning of period	$	21,281	$	15,433	$	15,433
Add: provision for contractual allowances	6,673		20,916		4,592
Less: realized contractual adjustments	(3,185)		(15,068)		(3,477)
Balance, end of period	$	24,769	$	21,281	$	16,548

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, United States 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. Centers for Medicare and Medicaid Services (“CMS”), accounted for approximately 14% and 27% of the Company’s revenue for the three months ended March 31, 2021, and 2020, respectively. CMS accounted for 14% and 20% of accounts receivable at March 31, 2021 and December 31, 2020, respectively.

The Company’s revenue is generated primarily from the provision of its cardiac rhythm monitoring service, the Zio XT service. The Zio XT is a cardiac rhythm monitoring service that has a patient wear period of up to 14 days and is billable when the monitoring reports are delivered to the healthcare provider, which is also when the service is complete and the Company recognizes revenue. The time from when the patient has the Zio XT device applied to the time the report is posted is generally around 20 days. The Company has concluded that the Zio XT service is one performance obligation on the basis that the

The Zio AT mobile cardiac telemetry monitor, a wearable patch-based biosensor, offers what the Zio XT offers plus the additional capability of transmissions during the wear period to assist physicians in diagnosing and treating the small percentage of the population requiring more timely action. During the wear period, physicians will receive notifications if there are significant events that meet predetermined arrhythmia detection criteria. The Zio AT service revenue is recognized ratably over the prescription period.

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.

•Non-contracted third-party payors – Non-contracted commercial and government payors often reimburse out-of-network rates provided under the relevant CPT codes on a case-by-case basis. The transaction price used for determining revenue recognition is based on factors including an average of the Company’s historical collection experience for its non-contracted services. This rate is reviewed at least quarterly.

The Company is utilizing the portfolio approach practical expedient under ASC 606 for revenue recognition 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. 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 we bill patient co-payments and deductibles and from time to time we 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.

For non-contracted portfolios, the Company is providing an implicit price concession due to the lack of a contracted rate with the underlying payor, the result of which requires the Company to estimate the transaction price based on historical cash collections utilizing the expected value method. All subsequent adjustments to the transaction price are recorded as an adjustment to revenue.

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 collection indicates 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.

The Company disaggregates revenue from contracts with customers by payor type. The Company believes these categories aggregate the payor types by nature, amount, timing and uncertainty of its revenue streams. Disaggregated revenue by payor type and major service line for three months ended March 31, 2021 and March 31, 2020 were as follows (in thousands):

ASC 606 requires an entity to present a revenue contract as a contract liability when the Company has an obligation to transfer goods or services to a customer for which the Company has received consideration from the customer, or an amount of consideration from the customer is due and unconditional (whichever is earlier).

Certain of the Company’s customers pay the Company directly for the Zio XT service upon shipment of devices. Such advance payments are contract liabilities and are recorded as deferred revenue on the Condensed Balance Sheets and revenue is recognized when reports are delivered to the healthcare provider. During the three months ended March 31, 2021, $0.9 million relating to the contract liability balance at the beginning of 2021 was recognized as revenue. Total revenue recognized during the three months ended March 31, 2020 that was included in the contract liability balance at the beginning of 2020 was $1.2 million.

The Company measures its stock-based awards made to employees based on the estimated fair values of the awards as of the grant date. The fair value of market condition awards is determined using the Monte-Carlo option pricing model and the fair value of stock options is determined using the Black-Scholes option pricing model. 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 Program (“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.