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Summary of significant accounting policies | 12 Months Ended
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Dec. 31, 2020
Summary of significant accounting policies |
Summary of significant accounting policies | 2. Summary of significant accounting policies Basis of presentation and consolidation Our consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). The accompanying consolidated financial statements include our accounts and the accounts of our majority owned subsidiaries. We consolidate our 70% ownership of Chicago Concourse Development Group, LLC and our 75% ownership of Boingo Holding Participacoes Ltda. in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 810, Consolidation. Other parties’ interests in consolidated entities are reported as non-controlling interests. All intercompany balances and transactions have been eliminated in consolidation. In December 2019, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which simplifies the accounting for income taxes. The standard removes certain ASC 740 exceptions to reduce the cost and complexity of its application including: i) the exception to the “with-and-without” approach for intraperiod tax allocation when there was a loss from continuing operations and income or a gain from other items such as discontinued operations of other comprehensive income; ii) two exceptions with respect to accounting for outside basis differences of equity method investments and foreign subsidiaries; and iii) the exception to limit the income tax benefit recognized in the interim period in cases where the year-to-date loss exceeded the anticipated loss for the year. The standard also clarified and amended existing guidance including, but not limited to: i) when a step-up in the tax basis of goodwill should be considered part of the business combination in which the book goodwill was originally recognized and when it should be considered a separate transaction; and ii) accounting for tax effects, both deferred and current, in the interim period that includes the enactment date. The standard is effective for annual periods beginning after December 15, 2020, and interim periods within those reporting periods. Early adoption is permitted with any adjustments reflected as of the beginning of the fiscal year of adoption. We adopted ASU 2019-12 on January 1, 2020 and the adoption of this standard did not have a material impact on our consolidated financial statements. In August 2018, the FASB issued ASU 2018-15, Intangibles—Goodwill and Other—Internal Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, which requires customers to apply the same criteria for capitalizing implementation costs incurred in a cloud computing arrangement that is hosted by the vendor as they would for an arrangement that has a software license. The standard is effective for interim and annual periods beginning after December 15, 2019 and early adoption is permitted. The standard can be adopted prospectively or retrospectively. We adopted ASU 2018-15 on January 1, 2020 on a prospective basis for any new implementation costs incurred in a cloud computing arrangement that is hosted by the vendor. The adoption of this standard did not have a material impact on our consolidated financial statements. In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326), which replaces the incurred loss methodology with an expected loss methodology that is referred to as the current expected credit loss (“CECL”) methodology. The measurement of expected credit losses under the CECL methodology is applicable to financial assets measured at amortized cost, including loan receivables and held-to-maturity debt securities. It also applies to off-balance sheet credit exposures not accounted for as insurance (loan commitments, standby letters of credit, financial guarantees, and other similar investments) and net investments in leases recognized by the lessor in accordance with ASC 842 on leases. In addition, the standard made changes to the accounting for available-for-sale debt securities. One such change is to require credit losses to be presented as an allowance rather than as a write-down on available-for-sale debt securities. Available-for-sale accounting recognizes that values may be realized either through collection of contractual cash flows or through the sale of the security. Therefore, the amendments limit the amount of the allowance for credit losses to the amount by which fair value is below amortized cost because the classification as available-for-sale is premised on an investment strategy that recognizes that the investment could be sold at fair value, if cash collection would result in the realization of an amount less than fair value. The standard is effective for interim and annual periods beginning after December 15, 2019 and early adoption is permitted. The standard will be adopted under the modified-retrospective approach with the prospective transition approach required for debt securities for which an other-than-temporary impairment had been recognized before the effective date. We adopted ASU 2016-13 on January 1, 2020 and the adoption of this standard did not have a material impact on our consolidated financial statements. In February 2016, the FASB issued a new standard related to leases, which was codified into Accounting Standards Codification ("ASC") 842, Leases. ASC 842 requires lessees to recognize assets and liabilities for all leases with lease terms of more than 12 months on the balance sheet. Under ASC 842, the recognition, measurement, and presentation of expenses and cash flows arising from a lease by a lessee will depend on its classification as a finance or operating lease. On January 1, 2019, we adopted ASC 842 using the modified retrospective transition approach. ASC 842 permits two methods of adoption and we elected to apply the guidance to each lease that had commenced as of January 1, 2019 with a cumulative-effect adjustment to the opening balance of retained earnings as of that date. ASC 842 permits various optional transition practical expedients. The discount rate used to calculate the present value of the future payments was determined as of January 1, 2019 for existing lease contracts and was generally based on our incremental borrowing rate as of January 1, 2019 commensurate with the remaining lease term. We also elected the package of practical expedients which included the following: (i) an entity need not reassess whether any expired or existing contracts are or contain leases; (ii) an entity need not reassess the lease classification for any expired or existing leases; and (iii) an entity need not reassess initial direct costs for any existing leases. The standard had a material impact on our consolidated balance sheet but did not have an impact on our consolidated statement of operations and our consolidated statement of cash flows. The most significant impact was the recognition of right-of-use ("ROU") assets and liabilities related to our operating leases, while our accounting for finance leases remained substantially unchanged. Adoption of the new standard resulted in the recording of $16,916 of operating lease ROU assets and $22,338 of operating lease ROU liabilities as of January 1, 2019. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers, which replaced the accounting standards for revenue recognition under FASB ASC 605, Revenue Recognition, with a single comprehensive five-step model, eliminating industry-specific accounting rules. The core principle is to recognize revenue upon the transfer of control of goods or services to a customer at an amount that reflects the consideration expected to be received. The FASB amended several aspects of the guidance after the issuance of ASU 2014-09, and the new revenue recognition accounting standard, as amended, was codified within ASC 606, Revenue from Contracts with Customers. On January 1, 2018, we adopted ASC 606 using the modified retrospective method applied to those contracts which were not completed as of January 1, 2018. Results for reporting periods beginning on January 1, 2018 are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported in accordance with ASC 605. Adoption of ASC 606 using the modified retrospective method required us to record a cumulative effect adjustment, net of tax, to accumulated deficit and non-controlling interests of $3,257 and $69, respectively, on January 1, 2018. In addition, adoption of the standard resulted in the following changes to the consolidated balance sheet as of January 1, 2018: ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ |  | January 1, 2018 |  | Adjustment for |  | January 1, 2018
​ | ​ | (Per ASC 605) | ​ | Adoption | ​ | (Per ASC 606)
Accounts receivable, net | ​ | $ | 26,148 | ​ | $ | (1,069) | ​ | $ | 25,079
Prepaid expenses and other current assets | ​ | $ | 6,369 | ​ | $ | 170 | ​ | $ | 6,539
Other assets | ​ | $ | 10,082 | ​ | $ | (2,179) | ​ | $ | 7,903
Deferred revenue, current | ​ | $ | 61,708 | ​ | $ | 14,176 | ​ | $ | 75,884
Deferred revenue, net of current portion | ​ | $ | 149,168 | ​ | $ | (20,580) | ​ | $ | 128,588
​ The changes to the consolidated balance sheet as of January 1, 2018 were primarily due to the following factors: (i) reclassification of unbilled receivables (contract assets) to a contra-liability account under ASC 606; and (ii) recognition of revenue related to our single performance obligation for our DAS contracts monthly over the contract term once the customer has the ability to access the DAS network and we commence maintenance on the DAS network under ASC 606 as compared to recognition of build-out fees for our DAS contracts monthly over the term of the estimated customer relationship period once the build-out is complete and minimum monthly access fees for our DAS contracts monthly over the term of the telecom operator agreement under ASC 605. The changes to the consolidated balance sheet as of January 1, 2018 are reflected as non-cash changes within cash provided by operating activities in our consolidated statement of cash flows for the year ended December 31, 2018. Use of estimates The preparation of accompanying consolidated financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the dates of the accompanying consolidated financial statements, and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates. Assets and liabilities which are subject to significant judgment and the use of estimates include the allowance for doubtful accounts, recoverability of goodwill and long-lived assets, valuation allowances with respect to deferred tax assets, useful lives associated with property and equipment, valuation of ROU assets and ROU liabilities, valuation and useful lives of intangible assets, contract assets and contract liabilities including estimates of variable consideration, and the valuation and assumptions underlying stock-based compensation and other equity instruments. On an ongoing basis, we evaluate our estimates compared to historical experience and trends, which form the basis for making judgments about the carrying value of assets and liabilities. Concentrations of credit risk Financial instruments that potentially subject us to significant concentrations of credit risk consist primarily of cash and cash equivalents, marketable securities, and accounts receivable. We extend credit based upon the evaluation of the customer’s financial condition and generally collateral is not required. We maintain an allowance for doubtful accounts based upon expected collectability of accounts receivable. We primarily estimate our allowance for doubtful accounts based on a specific review of significant outstanding accounts receivable. In April 2020, T-Mobile US Inc. announced that it had officially completed its merger with Sprint Corporation to create the New T-Mobile (collectively, “T-Mobile”). For the years ended December 31, 2020, 2019, and 2018, entities affiliated with T-Mobile accounted for 21%, 20%, and 26%, respectively, of total revenue. For the years ended December 31, 2020 and 2019, entities affiliated with AT&T Inc. accounted for 13% and 12%, respectively of total revenue. For the years ended December 31, 2020, 2019, and 2018, entities affiliated with Verizon Communications Inc. accounted for 11%, 11%, and 11%, respectively of total revenue. At December 31, 2020, entities affiliated with AT&T Inc., entities affiliated with Verizon Communications Inc., and T-Mobile accounted for 27%, 11%, and 13%, respectively, of the total accounts receivable, net. At December 31, 2019, entities affiliated with AT&T Inc. and T-Mobile accounted for 34% and 13%, respectively of the total accounts receivable, net. Cash and cash equivalents Cash and cash equivalents include highly liquid investments that are readily convertible into known amounts of cash with original maturities of three months or less when acquired. At December 31, 2020 and 2019, cash equivalents consisted of money market funds. Marketable securities Our marketable securities consist of available-for-sale securities with original maturities exceeding three months. According to ASC 320, Investments―Debt and Equity Securities, we have classified securities, which have readily determinable fair values and are highly liquid, as short-term because such securities are expected to be realized within a one year period. At December 31, 2020 and 2019, we had $4,565 and $40,214 in marketable securities. Marketable securities are reported at fair value with the related unrealized gains and losses reported as other comprehensive income (loss) until realized or until a determination is made that an other-than-temporary decline in market value has occurred. No significant unrealized gains and losses have been reported during the years presented. Factors considered by us in assessing whether an other-than-temporary impairment has occurred include the nature of the investment, whether the decline in fair value is attributable to specific adverse conditions affecting the investment, the financial condition of the investee, the severity and the duration of the impairment and whether we have the ability to hold the investment to maturity. When it is determined that an other-than-temporary impairment has occurred, the investment is written down to its market value at the end of the period in which it is determined that an other-than-temporary decline has occurred. The cost of marketable securities sold is based upon the specific identification method. Any realized gains or losses on the sale of investments are reflected as a component of interest income and other expense, net. For the year ended December 31, 2020, we had no significant realized or unrealized gains or losses from investments in marketable securities classified as available-for-sale. As of December 31, 2020 and 2019, we had $1 and $21, respectively, of cumulative unrealized gains, net of tax, which was $0 as of December 31, 2020 and 2019 due to the full valuation allowance established against our deferred tax assets, in accumulated other comprehensive loss. Fair value of financial instruments Fair value is defined as the price that would be received from selling an asset, or paid to transfer a liability, in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required or permitted to be recorded at fair value, we consider the principal or most advantageous market in which it would transact, and we consider assumptions that market participants would use when pricing the asset or liability. The accounting guidance for fair value measurement also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The standard establishes a fair value hierarchy based on the level of independent, objective evidence surrounding the inputs used to measure fair value. A financial instrument’s categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The fair value hierarchy is as follows:
| ● | Level 1—Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities.
| ● | Level 2—Quoted prices for identical assets and liabilities in markets that are not active, quoted prices for similar assets and liabilities in active markets or financial instruments for which significant inputs are observable, either directly or indirectly.
| ● | Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.
The carrying amount reflected in the accompanying consolidated balance sheets for cash equivalents, accounts receivable, accounts payable, and accrued expenses and other liabilities approximates fair value due to the short duration and nature of these financial instruments. Property and equipment Property and equipment are generally stated at historical cost, less accumulated depreciation and amortization. Our cost basis includes property and equipment acquired in business combinations that were initially recorded at fair value as of the date of acquisition. Maintenance and repairs are charged to expense as incurred and the cost of additions and betterments that increase the useful lives of the assets are capitalized. Depreciation and amortization are computed over the estimated useful lives of the related asset type using the straight-line method. The estimated useful lives for property and equipment are as follows: ​
​ | ​ | ​
Software |  | 2 to 5 years
Computer equipment | ​ | 3 to 5 years
Furniture, fixtures and office equipment | ​ | 3 to 5 years
Leasehold improvements | ​ | The shorter of the estimated useful life or the remaining term of the agreements, generally ranging from 2 to 25 years
​ Leasehold improvements are principally comprised of network equipment located at various managed and operated locations, primarily airports, under exclusive, long-term, non-cancelable contracts to provide wireless communication network access. We capitalize certain costs for our network equipment during the pre-construction period, which is the period during which costs are incurred to evaluate the site and continue to capitalize costs until the network equipment is substantially completed and ready for use. Cost for network equipment includes capitalized interest. Leases We determine if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use assets, current portion of operating leases, and long-term portion of operating leases in our consolidated balance sheets. Finance leases are included in property and equipment, net, current portion of finance leases, and long-term portion of finance leases in our consolidated balance sheets. Operating and finance lease ROU assets and ROU liabilities are recognized based on the present value of the future minimum lease payments over the lease term at the commencement date. As most of our leases for which we are lessee do not provide an implicit rate, we use our incremental borrowing rate based on the information available at the commencement date in determining the present value of future payments. The ROU asset also includes any lease payments made and excludes lease incentives and initial direct costs incurred. Our lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. We have lease agreements with lease and non-lease components, which are accounted for separately for the asset classes maintained. We exclude short-term leases with a lease term of 12 months or less at the commencement date from our consolidated balance sheets. Software development and cloud computing arrangement costs We capitalize costs associated with software developed or obtained for internal use and cloud computing arrangements when the preliminary project stage is completed, and it is determined that the software and cloud computing arrangements will provide significantly enhanced capabilities and modifications. These capitalized software development and cloud computing arrangement costs are included in property and equipment and prepaid and other current assets and other assets, respectively, and include external direct cost of services procured in developing or obtaining internal-use software and personnel and related expenses for employees who are directly associated with, and who devote time to internal-use software and cloud computing arrangement projects. Capitalization of these costs ceases once the project is substantially complete and the software and cloud computing arrangement is ready for its intended use. Once the software and cloud computing arrangement are ready for its intended use, the costs are amortized over the useful life of the software and term of the cloud computing arrangement, respectively. Post-configuration training and maintenance costs are expensed as incurred. Long-lived assets Intangible assets consist primarily of acquired venue contracts, backlog, customer and partnership relationships, non-compete agreements, technology, and patents and trademarks. We record intangible assets at fair value as of the date of acquisition and amortize these finite-lived assets over the shorter of the contractual life or the estimated useful life on a straight-line basis. We estimate the useful lives of acquired intangible assets based on factors that include the planned use of each acquired intangible asset, the expected pattern of future cash flows to be derived from each acquired intangible asset and contractual periods specified in the related agreements. We include amortization of acquired intangibles in amortization of intangible assets in the accompanying consolidated statements of operations. We perform an impairment review of long-lived assets held and used whenever events or changes in circumstances indicate that the carrying value may not be recoverable. Factors we consider important that could trigger an impairment review include but are not limited to: significant under-performance relative to projected future operating results, significant changes in the manner of our use of the acquired assets or our overall business and product strategies and significant industry or economic trends. When we determine that the carrying value of a long-lived asset may not be recoverable based upon the existence of one or more of these indicators, we determine the recoverability by comparing the carrying amount of the asset to net future undiscounted cash flows that the asset is expected to generate or other indices of fair value. We would then recognize an impairment charge equal to the amount by which the carrying amount exceeds the fair market value of the asset. Goodwill Goodwill represents the excess of the purchase price over the fair value of net assets acquired in connection with the acquisition of Concourse Communication Group, LLC in June 2006, Cloud 9 Wireless, Inc. in August 2012, Endeka Group, Inc. in February 2013, Electronic Media Systems, Inc. and Advanced Wireless Group, LLC in October 2013, and Elauwit Networks, LLC in August 2018. We test goodwill for impairment in accordance with guidance provided by FASB ASC 350, Intangibles—Goodwill and Other. Goodwill is tested for impairment at least annually at the reporting unit level or whenever events or changes in circumstances indicate that goodwill might be impaired. Events or changes in circumstances which could trigger an impairment review include a significant adverse change in legal factors or in the business climate, an adverse action or assessment by a regulator, unanticipated competition, a loss of key personnel, significant changes in the manner of our use of the acquired assets or the strategy for our overall business, significant negative industry or economic trends, or significant underperformance relative to expected historical or projected future results of operations. We perform our impairment test annually as of December 31st. Entities have the option to first assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount as a basis for determining whether it is necessary to perform the goodwill impairment test described in FASB ASC 350. If, after assessing qualitative factors, an entity determines it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, then performing the impairment test is unnecessary. The impairment loss, if any, is measured by comparing the implied fair value of the reporting unit goodwill with the carrying amount of goodwill. In October 2020, we completed our restructuring activities, which were initiated in December 2019. Prior to the completion of the restructuring activities, we had one reporting unit. At December 31, 2019, we tested our goodwill for impairment using a market-based approach and no impairment was identified as the fair value of our sole reporting unit was substantially in excess of its carrying amount. As a result of the restructuring, we currently have five reporting units: (i) carrier services for the provision of wireless and cellular services to our wireless customers (“Carrier Services”); (ii) military for the provision of wireless services on military bases (“Military”); (iii) private networks and emerging technologies for the provision of licensed, unlicensed, and shared spectrum services for our venue partners and non-telecom customers (“Private Networks and Emerging Technologies”); (iv) multifamily for the provision of wireless services for our multifamily property owners (“Multifamily”); and (v) legacy for the provision of our other services such as retail, advertising, and wholesale Wi-Fi services to enterprise customers (“Legacy”). In October 2020, immediately prior to the restructuring, we tested our goodwill for impairment using a market-based approach and no impairment was identified. We then estimated the fair value of each reporting unit using an income-based approach, specifically a discounted cash flow model. The cash flow model included significant judgments and assumptions related to revenue growth and discount rates. We reallocated our goodwill to the five reporting units using the relative fair value approach as follows: ​
​ | ​ | ​ | ​
​ | ​ | Goodwill
Carrier services | ​ | $ | 37,740
Military | ​ |  | 15,151
Multifamily | ​ |  | 3,062
Legacy | ​ | ​ | 1,829
Private networks and emerging technologies | ​ |  | 797
​ | ​ | $ | 58,579
​ On October 31, 2020, we tested our goodwill for impairment using an income-based approach and no impairment was identified as the fair value of our five reporting units were substantially in excess of their carrying amounts. On December 31, 2020, we tested our goodwill for impairment using a qualitative assessment and no impairment was identified. Convertible debt transactions We separately account for the liability and equity components of convertible debt instruments that can be settled in cash by allocating the proceeds from issuance between the liability component and the embedded conversion option in accordance with accounting for convertible debt instruments that may be settled in cash (including partial cash settlement) upon conversion. The value of the equity component is calculated by first measuring the fair value of the liability component, using the interest rate of a similar liability that does not have a conversion feature, as of the issuance date. The difference between the proceeds from the convertible debt issuance and the amount measured as the liability component is recorded as the equity component with a corresponding discount recorded on the debt. We recognize amortization of the resulting discount using the effective interest method as interest expense on our consolidated statements of operations. The equity component is not remeasured as long as it continues to meet the conditions for equity classification. We have allocated issuance costs incurred to the liability and equity components. Issuance costs attributable to the liability component are being amortized to expense over the respective term of the Convertible Notes, and issuance costs attributable to the equity components were netted with the respective equity component in additional paid-in capital. Simultaneously, we purchased capped call options from a financial institution to minimize the impact of potential dilution of our common stock upon conversion. The premium for the capped call options was recorded as additional paid-in capital on our consolidated balance sheets as the options are settleable in our common stock. Revenue recognition We generate revenue from several sources including: (i) telecom operators under long-term contracts for access to our DAS, macro tower, small cell, and Wi-Fi networks at our managed and operated locations, (ii) military and retail customers under subscription plans for month-to-month network access that automatically renew, and military and retail single-use access from sales of hourly, daily or other single-use access plans, (iii) arrangements with property owners for multifamily properties that provide for network installation and monthly Wi-Fi services and support for residents and employees or network-as-a-service (“NaaS”), (iv) arrangements with wholesale Wi-Fi customers that provide software licensing, network access, and/or professional services fees, and (v) display advertisements and sponsorships on our walled garden sign-in pages. Software licensed by our wholesale platform services customers can only be used during the term of the service arrangements and has no utility to them upon termination of the service arrangement. Revenues are recognized when a contract with a customer exists and control of the promised goods or services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services and the identified performance obligation has been satisfied. Contracts entered into at or near the same time with the same customer are combined and accounted for as a single contract if the contracts have a single commercial objective, the amount of consideration is dependent on the price or performance of the other contract, or the services promised in the contracts are a single performance obligation. Contract amendments are routine in the performance of our DAS, tower, small cell, wholesale Wi-Fi, and advertising contracts. Contracts are often amended to account for changes in contract specifications or requirements to expand network access services. In most instances, our DAS, tower, small cell, and wholesale Wi-Fi contract amendments are for additional goods or services that are distinct, and the contract price increases by an amount that reflects the standalone selling price of the additional goods or services; therefore, such contract amendments are accounted for as separate contracts. Contract amendments for our advertising contracts are also generally for additional goods or services that are distinct; however, the contract price does not increase by an amount that reflects the standalone selling price of the additional goods or services. Advertising contract amendments are therefore generally accounted for as contract modifications under the prospective method. Contract amendments to transaction prices with no change in remaining services are accounted for as contract modifications under the cumulative catch-up method. A performance obligation is a promise in a contract to transfer a distinct good or service to the customer and is the unit of account in Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers. A contract’s transaction price is allocated to each distinct performance obligation and is recognized as revenue when, or as, the performance obligation is satisfied, which typically occurs when the services are rendered. Determining whether products and services are considered distinct performance obligations that should be accounted for separately versus together may require significant judgment. Our contracts with customers may include multiple performance obligations. For such arrangements, we allocate revenue to each performance obligation based on its relative standalone selling price. We generally determine standalone selling prices based on the prices charged to customers. Judgment may be used to determine the standalone selling prices for items that are not sold separately, including services provided at no additional charge. Most of our performance obligations are satisfied over time as services are provided. We generally recognize revenue on a gross basis as we are primarily responsible for fulfilling the promises to provide the specified goods or services, we are responsible for paying all costs related to the goods or services before they have been transferred to the customer, and we have discretion in establishing prices for the specified goods or services. Revenue is presented net of any sales and value added taxes. Payment terms vary on a contract-by-contract basis, although terms generally include a requirement of payment within 30 to 60 days for non-recurring payments, the first day of the monthly or quarterly billing cycle for recurring payments for DAS, tower, small cell, and wholesale Wi-Fi contracts, and the first day of the month prior to the month that services are provided for Multifamily contracts. We apply a practical expedient for purposes of determining whether a significant financing component may exist for our contracts if, at contract inception, we expect that the period between when we transfer the promised good or service to the customer and when the customer pays for that good or service will be one year or less. In instances where the customer pays for a good or service one year or more in advance of the period when we transfer the promised good or service to the customer, we have determined our contracts generally do not include a significant financing component. The primary purpose of our invoicing terms is not to receive financing from our customers or to provide customers with financing but rather to maximize our profitability on the customer contract. Specifically, inclusion of non-refundable upfront fees in our long-term customer contracts increase the likelihood that the customer will be committed through the end of the contractual term and ensures recoverability of the capital outlay that we incur in expectation of the customer fulfilling its contractual obligations. We may also provide service credits to our customers if we fail to meet contractual monthly system uptime requirements and we account for the variable consideration related to these service credits using the most likely amount method. For contracts that include variable consideration, we estimate the amount of consideration at contract inception under the expected value method or the most likely amount method and include the amount of variable consideration that is not considered to be constrained. Significant judgment is used in constraining estimates of variable consideration. We update our estimates at the end of each reporting period as additional information becomes available. Timing of revenue recognition may differ from the timing of invoicing to customers. We record unbilled receivables (contract assets) when revenue is recognized prior to invoicing, deferred revenue (contract liabilities) when revenue is recognized after invoicing, and receivables when we have an unconditional right to consideration to invoice and receive payment in the future. We present our DAS, Multifamily, and Legacy wholesale Wi-Fi contracts in our consolidated balance sheet as either a contract asset or a contract liability with any unconditional rights to consideration presented separately as a receivable. Our other customer contracts generally do not have any significant contract asset or contract liability balances. Generally, a significant portion of the billing for our DAS contracts occurs prior to revenue recognition, resulting in our DAS contracts being presented as contract liabilities. In contrast, our Legacy wholesale Wi-Fi contracts and Multifamily network-as-a-service (“NaaS”) contracts that contain recurring fees with annual escalations are generally presented as contract assets as revenue is recognized prior to invoicing. Our Multifamily network construction, service and support contracts can be presented as either contract liabilities or contract assets primarily as a result of timing of invoicing for the network installations. We recognize an asset for the incremental costs of obtaining a contract with a customer if we expect the benefit of those costs to be longer than one year. We have determined that certain sales incentive programs meet the requirements to be capitalized. Total capitalized costs to obtain a contract were immaterial during the years ended December 31, 2020 and 2019 and are included in prepaid expenses and other current assets and non-current other assets on our consolidated balance sheets. We apply a practical expedient to expense costs as incurred for costs to obtain a contract with a customer when the amortization period would have been one year or less. Contract costs are evaluated for impairment in accordance with ASC 310, Receivables. Carrier services DAS, towers, and small cells We enter into long-term contracts with telecom operators for access to our DAS, tower, and small cell networks at our managed and operated locations. The initial term of our DAS, tower, and small cell contracts with telecom operators can range up to 20 years and the agreements generally contain renewal options. Some of our contracts provide termination for convenience clauses that may or may not include substantive termination penalties. We apply judgment in determining the contract term, the period during which we have present and enforceable rights and obligations. Our DAS, tower, and small cell customer contracts generally contain a single performance obligation—provide non-exclusive access to our DAS, tower, and small cell networks to provide telecom operators’ customers with access to the licensed wireless spectrum, together with providing telecom operators with construction, installation, optimization/engineering, maintenance services and agreed-upon storage space for the telecom operators’ transmission equipment, each related to providing such licensed wireless spectrum to the telecom operators. The performance obligation is considered a series of distinct services as the performance obligation is satisfied over time and the same time-based input method would be used to measure our progress toward complete satisfaction of the performance obligation to transfer each distinct service in the series to the customer. Our contract fee structure generally includes a non-refundable upfront fee and we evaluated whether customer options to renew services give rise to a material right that should be accounted for as a separate performance obligation because of those non-refundable upfront fees. We apply significant judgment in determining whether the customer options to renew services give rise to a material right that should be accounted for as a separate performance obligation. We believe that a material right generally does not exist for our DAS, tower, and small cell customer contracts that contain renewal options because the telecom operators’ decision to renew is highly dependent upon our ability to maintain our exclusivity as the DAS, tower, and small cell service provider at the venue location and our limited operating history with venue and customer renewals. The telecom operators will make the decision to incur the capital improvement costs at the venue location irrespective of our remaining exclusivity period with the venue as the telecom operators expect that the assets will continue to be serviced regardless of whether we will remain such exclusive DAS, tower, and small cell service provider. Our contracts also provide our DAS, tower, and small cell customers with the option to purchase additional future services such as upgrades or enhancements. This option is not considered to provide the customer with a material right that should be accounted for as a separate performance obligation since the cost of the additional future services depends entirely on the market rate of such services at the time such services are requested, and we are not automatically obligated to stand ready to deliver these additional goods or services as the customer may reject our proposal. Periodically, we install and sell DAS, tower, and small cell networks to customers where we do not have service contracts or remaining obligations beyond the installation of those networks, and we recognize build-out fees for such projects as revenue when the installation work is completed and the network has been accepted by the customer or using a cost-to-cost method over the network installation period depending on when control is transferred to the customer. Our contract fee structure may include varying components of an upfront build-out fee and recurring access, maintenance, and other fees. The upfront build-out fee is generally structured as a firm-fixed price or cost-plus arrangement and becomes payable as certain contract and/or construction milestones are achieved. Our DAS, tower, and small cell networks are generally neutral host networks that can accommodate multiple telecom operators. Some of our DAS customer contracts provide for credits that may be issued to existing telecom operators for additional telecom operators subsequently joining the DAS network. The credits are generally based upon a fixed dollar amount per additional telecom operator, a fixed percentage amount of the original build-out fee paid by the telecom operator per additional telecom operator, or a proportionate share based upon the split among the relevant number of telecom operators for the actual costs incurred by all telecom operators to construct the DAS network. In most cases, there is significant uncertainty on whether additional telecom operator contracts will be executed at inception of the contract with the existing telecom operator. We believe that the upfront build-out fee is fixed consideration once the build-out is complete and any subsequent credits that may be issued would be accounted for in a manner similar to a contract modification under the prospective method because (i) the execution of customer contracts with additional telecom carriers is at our sole election and (ii) we would not execute agreements with additional telecom carriers if it would not increase our revenues and gross profits at the venue level. Further, the credits issued to the existing telecom operator changes the transaction price on a go-forward basis, which corresponds with the decline in service levels for the existing telecom operator once the neutral host DAS network can be accessed by the additional telecom operator. The recurring access, maintenance, and other fees generally escalate on an annual basis. The recurring fees are variable consideration until the contract term and annual escalation dates are fixed. We estimate the variable consideration for our recurring fees using the most likely amount method based on the expected commencement date for the services. We evaluate our estimates of variable consideration each period and record a cumulative catch-up adjustment in the period in which changes occur for the amount allocated to satisfied performance obligations. We generally recognize revenue related to our single performance obligation for our DAS, tower, and small cell customer contracts monthly over the contract term once the customer may access the DAS, tower, and small cell network and we commence maintenance on the DAS, tower, and small cell network. Wi-Fi offload We enter into contracts with telecom operators to move traffic from their licensed cellular networks onto our Wi-Fi networks at our managed and operated locations. Our offload contracts generally contain a single performance obligation—provide non-exclusive rights to access our Wi-Fi networks to provide telecom operators' end customers with access to the high-speed broadband network that may be bundled together with integration services, support services, and/or performance of standard maintenance. The performance obligation is considered a series of distinct services as the performance obligation is satisfied over time and the same time-based input method or usage-based output method would be used to measure our progress toward complete satisfaction of the performance obligation to transfer each distinct service in the series to the customer. Our contract fee structure includes recurring fees that are accounted for as fixed consideration. We generally recognize revenue related to our single performance obligation for our offload customer contract monthly over the contract term once services have launched. Military Retail Military retail customers must review and agree to abide by our standard “Customer Agreement (With Acceptable Use Policy) and End User License Agreement” before they are able to sign up for our subscription or single-use Wi-Fi network access services. Our Military retail customer contracts generally contain a single performance obligation—provide non-exclusive access to Wi-Fi services, together with performance of standard maintenance, customer support, and the Wi-Finder app to facilitate seamless connection to the Company’s Wi-Fi network. The performance obligation is considered a series of distinct services as the performance obligation is satisfied over time and the same time-based input method would be used to measure our progress toward complete satisfaction of the performance obligation to transfer each distinct service in the series to the customer. Our contracts also provide our Military retail subscription customers with the option to renew the agreement when the subscription term is over. We do not consider this option to provide the customer with a material right that should be accounted for as a separate performance obligation because the customer would not receive a discount if it decided to renew and the option to renew is cancellable within 5 days’ notice prior to the end of the then current term by either party. The contract transaction price is determined based on the subscription or single-use plan selected by the customer. Our Military retail service plans are for fixed price services as described on our website. From time to time, we offer promotional discounts that result in an immediate reduction in the price paid by the customer. Subscription fees from Military retail customers are paid monthly in advance. We provide refunds for our Military retail services on a case-by-case basis. Refunds and credit card chargeback amounts are not significant and are recorded as contra-revenue in the period the refunds are made, or chargebacks are received. Subscription fee revenue is recognized ratably over the subscription period. Revenue generated from Military retail single-use access is recognized when access is provided, and the performance obligation is satisfied. Bulk services We enter into short-term and long-term contracts with the U.S. government to provide network installation services and Wi-Fi services at specified locations on military bases on a bulk basis. The U.S. government may modify, curtail or terminate its contracts with us, either at its convenience or for default based on performance. Our Military bulk services customer contracts generally contain a single performance obligation—provide non-exclusive rights to access our Wi-Fi networks to provide military personnel with access to the high-speed broadband network that may be bundled together with integration services, support services, and/or performance of standard maintenance. The performance obligation is considered a series of distinct services as the performance obligation is satisfied over time and the same time-based input method would be used to measure our progress toward complete satisfaction of the performance obligation to transfer each distinct service in the series to the customer. Our contract fee structure generally includes a non-refundable upfront fee and we evaluated whether customer options to renew services give rise to a material right that should be accounted for as a separate performance obligation because of those non-refundable upfront fees. We apply significant judgment in determining whether the customer options to renew services give rise to a material right that should be accounted for as a separate performance obligation. We believe that a material right generally exists for our Military bulk services customer contracts that contain renewal options because of our successful history of renewing our contracts with the U.S. government. Our contract fee structure may include varying components of an upfront build-out fee and recurring access fees. The upfront build-out fee is generally structured as a firm-fixed price arrangement and becomes payable as certain contract and/or construction milestones are achieved. The recurring fees may include escalations and are variable consideration until the contract term becomes fixed. We generally recognize revenue related to our single performance obligation for our Military bulk services customer contract monthly on a straight-line basis, where applicable, over the contract term once the customer has accepted the network installation services, where applicable, and services have launched. Private networks and emerging technologies Our customer contracts for private networks and emerging technologies generally contain two performance obligations: (i) install the network required to provide licensed, unlicensed, and shared spectrum services; and (ii) provide management services for those installed networks. Our contracts may also provide our customers with the option to renew the agreement. We do not consider this option to provide the customer with a material right that should be accounted for as a separate performance obligation because the customer would not receive a discount if it decided to renew and the option to renew is generally cancellable by either party subject to the notice of non-renewal requirements specified in the contract. Our contract fee structure generally includes a network installation fee and recurring service fees. The network installation fee is generally structured as a firm-fixed price arrangement and becomes payable as certain contract and/or installation milestones are achieved. Title to the equipment is generally owned by the customer once it is delivered and/or installed. We generally recognize revenue related to our network installation performance obligation using a cost-to-cost method over the network installation period. The recurring fees commence once the network is launched with recurring fees generally based upon a fixed fee that may include annual escalations. We recognize revenue related to the recurring fees on a monthly basis over the contract term as the services are rendered and the performance obligation is satisfied. Multifamily We enter into long-term contracts with property owners for the installation of developer-owned or Boingo-owned Wi-Fi networks and the provision of recurring Wi-Fi services and technical support once the Wi-Fi networks are constructed. The initial term of our contracts with property owners can range up to ten years and the contracts may contain renewal options. Some of our contracts provide termination for convenience clauses that may or may not include substantive termination penalties. We apply judgment in determining the contract term, which is the period during which we have present and enforceable rights and obligations. Developer-owned networks Our customer contracts for developer-owned Wi-Fi networks that we construct and provide service and support for generally contain two performance obligations: (i) install the network required to provide Wi-Fi services; and (ii) provide Wi-Fi services and technical support to the residents and employees. Our contracts may also provide our property owners with the option to renew the agreement. We do not consider this option to provide the property owner with a material right that should be accounted for as a separate performance obligation because the property owner would not receive a discount if it decided to renew and the option to renew is generally cancellable by either party subject to the notice of non-renewal requirements specified in the contract. Our contracts may also provide our customers with the option to purchase additional future services. We do not consider this option to provide the customer with a material right that should be accounted for as a separate performance obligation since the cost of the additional future services are generally at market rates for such services and we are not automatically obligated to stand ready to deliver these additional goods or services because the customer may reject our proposal. Our contract fee structure generally includes a network installation fee and recurring Wi-Fi service and support fees. The network installation fee is generally structured as a firm-fixed price arrangement and becomes payable as certain contract and/or installation milestones are achieved. We generally estimate variable consideration for unpriced change orders using the most likely amount method based on the expected price for those services. If network installations are not completed by specified dates, we may be subject to network installation penalties. We estimate the variable consideration for our network installation fees using the most likely amount method based on the amount of network installation penalties we expect to incur. Title to the network generally transfers to the property owner once installation is completed and the network has been accepted. We generally recognize revenue related to our network installation performance obligation using a cost-to-cost method over the network installation period. We may provide latent defect warranties for materials and installation labor services related to our network installation services. Our warranty obligations are generally not accounted for as separate performance obligations as warranties cannot be separately purchased and warranties do not provide a service in addition to the assurance that the network will function as expected. The recurring fees commence once the network is launched with recurring fees generally based upon a fixed or variable occupancy rate. The recurring Wi-Fi service fees may be adjusted prospectively for changes in circuit and/or video content costs, and Wi-Fi support fees may escalate on an annual basis. We estimate the variable consideration for our recurring fees using the expected value method with the exception of the variable consideration related to actual occupancy rates, which we record when we have the contractual right to bill. We evaluate our estimates of variable consideration each period and record a cumulative catch-up adjustment in the period in which changes occur for the amount allocated to satisfied performance obligations. We recognize revenue related to the recurring fees on a monthly basis over the contract term as the Wi-Fi services and support is rendered, and the performance obligation is satisfied. Boingo-owned networks / NaaS Our customer contracts for Boingo-owned Wi-Fi networks are generally structured as NaaS arrangements for the provision of Wi-Fi services and technical support for residents and employees at the property as our Boingo-owned Wi-Fi networks may be used by other retail and wholesale Wi-Fi customers. Our NaaS contracts generally contain a single performance obligation—provide non-exclusive rights to access our Wi-Fi networks to provide residents and employees of the property with access to the high-speed broadband network that may be bundled together with technical support services and/or performance of standard network maintenance. The performance obligation is considered a series of distinct services as the performance obligation is satisfied over time and the same time-based input method or usage-based output method would be used to measure our progress toward complete satisfaction of the performance obligation to transfer each distinct service in the series to the customer. Our contract fee structure generally includes recurring fees that generally escalate on an annual basis that are accounted for as fixed consideration. We generally recognize revenue related to our single performance obligation for our NaaS contracts monthly on a straight-line basis, where applicable, over the contract term once services have launched. Legacy Comes with Boingo and Wholesale Wi-Fi We enter into long-term contracts with financial institutions and other enterprise customers who provide access to our Wi-Fi footprint as a value-added service for their customers. We also enter into long-term contracts with enterprise customers such as cable companies, technology companies, and enterprise software/services companies, that pay us usage-based Wi-Fi network access and software licensing fees to allow their customers’ access to our footprint worldwide. The initial term of our contracts with Comes with Boingo and wholesale Wi-Fi customers generally range up to five years and the agreements generally contain renewal options. Some of our contracts provide termination for convenience clauses that may or may not include substantive termination penalties. We apply judgment in determining the contract term, the period during which we have present and enforceable rights and obligations. Our Comes with Boingo and wholesale Wi-Fi customer contracts generally contain a single performance obligation—provide non-exclusive rights to access our Wi-Fi networks to provide wholesale Wi-Fi customers’ end customers with access to the high-speed broadband network that may be bundled together with integration services, support services, and/or performance of standard maintenance. The performance obligation is considered a series of distinct services as the performance obligation is satisfied over time and the same time-based input method or usage-based output method would be used to measure our progress toward complete satisfaction of the performance obligation to transfer each distinct service in the series to the customer. Our contracts may also provide our enterprise customers with the option to renew the agreement. This option is not considered to provide the customer with a material right that should be accounted for as a separate performance obligation because the customer would not receive a discount if it decided to renew and the option to renew is generally cancellable by either party subject to the notice of non-renewal requirements specified in the contract. Our contracts may also provide our wholesale Wi-Fi customers with the option to purchase additional future services. We do not consider this option to provide the customer with a material right that should be accounted for as a separate performance obligation since the cost of the additional future services are generally at market rates for such services and we are not automatically obligated to stand ready to deliver these additional goods or services because the customer may reject our proposal. Our contract fee structure may include varying components of a minimum fee and usage-based fees. Minimum fees represent fixed price consideration while usage-based fees represent variable consideration. With respect to variable consideration, our commitment to our Comes with Boingo and wholesale Wi-Fi customers consists of providing continuous access to the network. It is therefore a single performance obligation to stand ready to perform and we allocate the variable fees charged for usage when we have the contractual right to bill. The variable component of revenue is recognized based on the actual usage during the period. Comes with Boingo and wholesale Wi-Fi revenue is recognized as it is earned over the relevant contract term with variable consideration recognized when we have the contractual right to bill. Retail Revenue recognition for our Legacy retail customers is the same as for our Military retail customers. Refer to the Military retail section for further information. Tenant services We offer our venue partners and their tenants the ability to implement a turnkey Wi-Fi solution through a Wi-Fi network infrastructure that we install, manage and operate. Our turnkey solutions for our venue partners include a variety of service models that are supported through a mix of wholesale Wi-Fi, retail, and advertising revenue. Our managed services and tenant services contracts generally contain a single performance obligation—provide non-exclusive rights to access our Wi-Fi networks to provide end customers with access to the high-speed broadband network that may be bundled together with support services and/or performance of standard maintenance. The performance obligation is considered a series of distinct services as the performance obligation is satisfied over time and the same time-based input method or usage-based output method would be used to measure our progress toward complete satisfaction of the performance obligation to transfer each distinct service in the series to the customer. Our contract fee structure may include varying components of an upfront build-out fee and recurring access fees. The upfront build-out fee is generally structured as a firm-fixed price arrangement and becomes payable as certain contract and/or construction milestones are achieved. The recurring fees may include escalations and are variable consideration until the contract term becomes fixed. We generally recognize revenue related to our single performance obligation for our managed services and tenant services customer contract monthly on a straight-line basis, where applicable, over the contract term once the customer has accepted the network installation services, where applicable, and services have launched. Periodically, we install and sell Wi-Fi networks to customers where we do not have service contracts or remaining obligations beyond the installation of those networks, and we recognize build-out fees for such projects as revenue when the installation work is completed, and the network has been accepted by the customer or using a cost-to-cost method over the network installation period depending on when control is transferred to the customer. Advertising We generally enter into short-term cancellable insertion orders with our advertising customers for advertising campaigns that are served at our managed and operated locations and other locations where we solely provide authorized access to a partner’s Wi-Fi network through sponsored and promotional programs. Our sponsorship advertising arrangements are generally priced under a cost per engagement structure, which is a set price per click or engagement, or a cost per install structure for third party application downloads. Our display advertising arrangements are priced based on cost per thousand impressions. Insertion orders may also include bonus items. Our advertising customer contracts may contain multiple performance obligations with each distinct service. These distinct services may include an advertisement video or banner impressions in the contract bundled with the requirement to provide network, space on the website, and integration of customer advertisement onto the website, and each is generally considered to be its own performance obligation. The performance obligations are considered a series of distinct services as the performance obligations are satisfied over time and the same action-based output method would be used to measure our progress toward complete satisfaction of the performance obligation to transfer each distinct service in the series to the customer. The contract transaction price is comprised of variable consideration based on the stated rates applied against the number of units delivered inclusive of the bonus units subject to the maximums provided for in the insertion order. It is customary for us to provide additional units over and above the amounts contractually required; however, there are a number of factors that can also negatively impact our ability to deliver the units required by the customer such as service outages at the venue resulting from power or circuit failures and customer cancellation of the remaining undelivered units under the insertion order due to campaign performance or budgetary constraints. Typically, the advertising campaign periods are short in duration. We therefore use the contractual rates per the insertion orders and actual units delivered to determine the transaction price each period end. The transaction price is allocated to each performance obligation based on the standalone selling price of each performance obligation. Advertising revenue is recognized ratably over the service period based on actual units delivered subject to the maximums provided for in the insertion order. Foreign currency translation Our Brazilian subsidiary uses the Brazilian Real as its functional currency. Assets and liabilities of our Brazilian subsidiary are translated to U.S. dollars at period-end rates of exchange, and revenues and expenses are translated at average exchange rates prevailing for each month. The resulting translation adjustments are made directly to a separate component of other comprehensive loss, which is reflected in stockholders’ equity in our consolidated balance sheets. As of December 31, 2020 and 2019, the Company had $(2,280) and $(1,447), respectively, of cumulative foreign currency translation adjustments, net of tax, which was $0 as of December 31, 2020 and 2019 due to the full valuation allowance established against our deferred tax assets, in accumulated other comprehensive loss. The functional currency for all of our other foreign subsidiaries is the U.S. dollar. Gains and losses from the revaluation of foreign currency transactions and monetary assets and liabilities are included in the consolidated statements of operations. For the years ended December 31, 2020, 2019, and 2018, we had no significant foreign currency transaction gains and losses. Cost of sales Cost of sales consist primarily of revenue share payments to venue owners where our managed and operated hotspots are located, usage-based fees to our roaming network partners for access to their networks, depreciation of equipment related to network build-out projects in our managed and operated locations, bandwidth and other Internet connectivity expenses in our managed and operated locations, and network installation, service and support costs for our Multifamily properties. Advertising, marketing and promotion costs Advertising production costs are generally expensed the first time the advertisement is run. No advertising production costs were capitalized for the years ended December 31, 2020, 2019 and 2018. Endorsement payments are expensed on a straight-line basis over the term of the contract. All other costs of advertising, marketing and promotion are expensed as incurred. Advertising expenses charged to operations totaled $1,908, $2,205 and $2,213 for the years ended December 31, 2020, 2019 and 2018, respectively. Stock-based compensation Our stock-based compensation consists of stock options, and restricted stock units (“RSU”) granted to employees and non-employees. We have shifted our stock-based compensation from stock options to RSUs and no stock options have been granted since 2014. We recognize stock-based compensation expense in accordance with guidance provided by FASB ASC 718, Compensation—Stock Compensation. We measure employee stock-based compensation cost at grant date, based on the estimated fair value of the award and recognize the cost on a straight-line basis over the employee requisite service period. We recognize stock-based compensation expense for performance-based RSUs when we believe that it is probable that the performance objectives will be met. Forfeitures are accounted for when they occur. Income taxes We account for income taxes in accordance with FASB ASC 740, Accounting for Income Taxes, which requires the recognition of deferred tax assets and liabilities for the future consequences of events that have been recognized in our accompanying consolidated financial statements or tax returns. The measurement of the deferred items is based on enacted tax laws. In the event the future consequences of differences between financial reporting bases and the tax bases of our assets and liabilities result in a deferred tax asset, ASC 740 requires an evaluation of the probability of being able to realize the future benefits indicated by such asset. A valuation allowance related to a deferred tax asset is recorded when it is more likely than not that some portion or the entire deferred tax asset will not be realized. As part of the process of preparing our accompanying consolidated financial statements, we are required to estimate our income taxes in each of the jurisdictions in which we operate. We also assess temporary differences resulting from differing treatment of items, such as deferred revenue, for tax and accounting differences. We record a valuation allowance to reduce the deferred tax assets to the amount of future tax benefit that is more likely than not to be realized. ASC 740 prescribes a recognition threshold and measurement methodology to recognize and measure an income tax position taken, or expected to be taken, in a tax return. The evaluation of a tax position is based on a two-step approach. The first step requires an entity to evaluate whether the tax position would “more likely than not” be sustained upon examination by the appropriate taxing authority. The second step requires the tax position be measured at the largest amount of tax benefit that is greater than 50% likely of being realized upon ultimate settlement. In addition, previously recognized benefits from tax positions that no longer meet the new criteria would no longer be recognized. Changes in recognition or measurement are reflected in the period in which the change occurs. Non-controlling interests Non-controlling interests are comprised of minority holdings in Chicago Concourse Development Group, LLC (“CCDG”) and Boingo Holding Participacoes Ltda (“BHPL”). Under the terms of the LLC agreement for CCDG, we are generally required to distribute annually to the CCDG non-controlling interest holders 30% of allocated net profits less capital expenditures of the preceding year. For the years ended December 31, 2020, 2019 and 2018, we made distributions of $262, $1,003 and $614, respectively, to non-controlling interest holders of CCDG. Under the terms of the LLC agreement for BHPL, we attributed profits and losses to the non-controlling interest in BHPL in proportion to their holdings. For the years ended December 31, 2020, 2019 and 2018, we made no distributions to the non-controlling interest holder of BHPL. Net loss per share attributable to common stockholders Basic net loss per share attributable to common stockholders is calculated by dividing loss attributable to common stockholders by the weighted average number of shares of common stock outstanding during the period. Diluted net loss per share attributable to common stockholders adjusts the basic weighted average number of shares of common stock outstanding for the potential dilution that could occur if stock options and RSUs were exercised or converted into common stock. Segment and geographic information In 2020, we completed our restructuring activities, which were initiated in December 2019. Prior to the completion of the restructuring activities, we operated as one reportable segment—a service provider of wireless connectivity solutions across our managed and operated network and aggregated network for mobile devices such as laptops, smartphones, tablets and other wireless-enabled consumer devices. This single segment was consistent with the internal organizational structure and the manner in which operations were reviewed and managed by our Chief Executive Officer, the chief operating decision maker. We currently have five reportable and operating segments: (i) carrier services for the provision of wireless and cellular services to our wireless customers (“Carrier Services”); (ii) military for the provision of wireless services on military bases (“Military”); (iii) private networks and emerging technologies for the provision of licensed, unlicensed, and shared spectrum services for our venue partners and non-telecom customers (“Private Networks and Emerging Technologies”); (iv) multifamily for the provision of wireless services for our multifamily property owners (“Multifamily”); and (v) legacy for the provision of our other services such as retail, advertising, and wholesale Wi-Fi services to enterprise customers (“Legacy”). Prior period segment results have been recast to conform to the current presentation. We evaluate reportable and operating segment performance primarily based on revenues and income (loss) from operations, which is our segment operating performance measure. The income (loss) from operations of each of the reportable and operating segments include only those costs which are specifically related to each reportable and operating segment, which consist primarily of cost of sales, sales and marketing, depreciation, and the direct costs of employees within those reportable and operating segments. We do not allocate corporate overhead costs or non-operating income and expenses to reportable and operating segments, which include unallocable overhead costs associated with our corporate offices, certain executive compensation including stock compensation, costs related to our accounting, finance, legal, engineering, marketing, and human resources departments, among others. Segment information under the new five reportable segment basis, with a reconciliation to the consolidated statements of operations, is summarized as follows: ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Year Ended December 31,
​ |  | 2020 |  | 2019 |  | 2018
Revenue: | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Carrier services | ​ | $ | 107,746 | ​ | $ | 115,806 | ​ | $ | 117,953
Military | ​ | ​ | 76,753 | ​ | ​ | 74,911 | ​ | ​ | 67,342
Multifamily | ​ |  | 21,567 | ​ |  | 25,008 | ​ |  | 11,228
Legacy | ​ | ​ | 29,134 | ​ | ​ | 46,058 | ​ | ​ | 54,248
Private networks and emerging technologies | ​ |  | 2,216 | ​ |  | 2,007 | ​ |  | 50
Total revenue | ​ | $ | 237,416 | ​ | $ | 263,790 | ​ | $ | 250,821
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Year Ended December 31,
​ |  | 2020 |  | 2019 |  | 2018
Income (loss) from operations: | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Carrier services | ​ | $ | 19,671 | ​ | $ | 30,043 | ​ | $ | 31,294
Military | ​ | ​ | 24,027 | ​ | ​ | 20,736 | ​ | ​ | 14,250
Multifamily | ​ |  | (6,690) | ​ |  | (7,225) | ​ |  | (3,030)
Legacy | ​ | ​ | 42 | ​ | ​ | 5,616 | ​ | ​ | 6,101
Private networks and emerging technologies | ​ |  | 1,266 | ​ |  | 1,963 | ​ |  | (26)
Unallocated overhead costs | ​ | ​ | (47,433) | ​ | ​ | (54,837) | ​ | ​ | (51,586)
Total loss from operations | ​ | ​ | (9,117) | ​ | ​ | (3,704) | ​ | ​ | (2,997)
Interest expense and amortization of debt discount | ​ | ​ | (9,004) | ​ | ​ | (8,618) | ​ | ​ | (2,400)
Interest income and other expense, net | ​ | ​ | 538 | ​ | ​ | 2,017 | ​ | ​ | 513
Loss before income taxes | ​ | $ | (17,583) | ​ | $ | (10,305) | ​ | $ | (4,884)
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Year Ended December 31,
​ |  | 2020 |  | 2019 |  | 2018
Depreciation and amortization of property and equipment and intangible assets: | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Carrier services | ​ | $ | 47,381 | ​ | $ | 41,210 | ​ | $ | 50,933
Military | ​ | ​ | 17,309 | ​ | ​ | 15,998 | ​ | ​ | 15,139
Multifamily | ​ |  | 3,117 | ​ |  | 2,741 | ​ |  | 1,075
Legacy | ​ | ​ | 7,770 | ​ | ​ | 8,103 | ​ | ​ | 9,101
Private networks and emerging technologies | ​ |  | 10 | ​ |  | — | ​ |  | —
Unallocated overhead costs | ​ | ​ | 7,014 | ​ | ​ | 7,381 | ​ | ​ | 6,299
Total depreciation and amortization of property and equipment and intangibles assets | ​ | $ | 82,601 | ​ | $ | 75,433 | ​ | $ | 82,547
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Year Ended December 31,
​ |  | 2020 |  | 2019 |  | 2018
Capital expenditures: | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Carrier services | ​ | $ | 86,404 | ​ | $ | 114,713 | ​ | $ | 83,764
Military | ​ | ​ | 9,934 | ​ | ​ | 7,339 | ​ | ​ | 7,852
Multifamily | ​ |  | 1,990 | ​ |  | 1,242 | ​ |  | 84
Legacy | ​ | ​ | 3,572 | ​ | ​ | 4,653 | ​ | ​ | 10,758
Private networks and emerging technologies | ​ |  | 206 | ​ |  | 318 | ​ |  | —
Unallocated capital expenditures | ​ | ​ | 4,156 | ​ | ​ | 5,431 | ​ | ​ | 6,272
Total capital expenditures | ​ | $ | 106,262 | ​ | $ | 133,696 | ​ | $ | 108,730
Assets allocated to each reportable and operating segment include property and equipment, net, goodwill, and intangible assets, net that are specifically identifiable for one of our reportable and operating segments. Our reportable and operating segments also represent reporting units for goodwill impairment testing purposes. Unallocated assets are those assets not directly related to a specific reportable and operating segment. Assets allocated to each reportable and operating segment, which a reconciliation to the consolidated balance sheet, are as follows:
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31,
​ |  | 2020 |  | 2019
Assets: | ​ | ​ | ​ | ​ | ​ | ​
Carrier services | ​ | $ | 364,484 | ​ | $ | 325,500
Military | ​ | ​ | 66,968 | ​ | ​ | 73,981
Multifamily | ​ |  | 12,713 | ​ |  | 13,772
Legacy | ​ | ​ | 18,591 | ​ | ​ | 23,402
Private networks and emerging technologies | ​ |  | 1,024 | ​ |  | 1,304
Unallocated other corporate assets | ​ | ​ | 112,699 | ​ | ​ | 162,508
Total assets | ​ | $ | 576,479 | ​ | $ | 600,467
All significant long-lived tangible assets are held in the United States of America. We do not disclose sales by geographic area because it would be impracticable to do so. Recent accounting pronouncements In August 2020, the FASB issued ASU 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging Contracts in Entity’s Own Equity (Subtopic 815-40), which eliminates the beneficial conversion and cash conversion accounting models for convertible instruments, amends the accounting for certain contracts in an entity’s own equity that are currently accounted for as derivatives because of specific settlement provisions, and modifies how particular convertible instruments and certain contracts that may be settled in cash or shares impact the diluted EPS calculation. The standard is effective for annual periods beginning after December 15, 2021, and interim periods within those reporting periods. Early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2020, including interim periods within those reporting periods. The standard can be adopted under the modified retrospective method or the full retrospective method. We have selected January 1, 2021 as our effective date and will be adopting the standard under the modified retrospective method. Adoption of ASU 2020-06 using the modified retrospective method will require us to record a cumulative effect adjustment, net of tax, to accumulated deficit of $6,566 on January 1, 2021. In addition, adoption of the standard will result in the following changes to the consolidated balance sheet as of January 1, 2021: ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ |  | January 1, 2021 |  | Adjustment for |  | January 1, 2021
​ | ​ | (Unadjusted) | ​ | Adoption | ​ | (Adjusted)
Property and equipment, net | ​ | $ | 406,328 | ​ | $ | (6,076) | ​ | $ | 400,252
Long-term debt | ​ | $ | 171,695 | ​ | $ | 27,279 | ​ | $ | 198,974
Additional paid-in capital | ​ | $ | 241,868 | ​ | $ | (39,921) | ​ | $ | 201,947
​ ​ The changes to the consolidated balance sheet as of January 1, 2021 were primarily due to the following factors: (i) reclassification of the equity component of our Convertible Notes related to the cash conversion feature to a liability thereby eliminating the debt discount; (ii) reclassification of debt issuance costs for the equity component of our Convertible Notes to a liability; (iii) adjustment of the amount of interest expense capitalized as part of our property and equipment; and (iv) reversal of $5,686 of income tax benefit related to the equity component of the Convertible Notes that was recorded as additional paid-in capital. As of December 31, 2020, we also have $27,949 of gross deferred tax liabilities related to the equity component of our Convertible Notes. The adoption of ASU 2020-06 will not have any impact on our net deferred tax as of January 1, 2021 due to the valuation allowance. Effective January 1, 2021, we will also calculate the dilutive effect of the Convertible Notes on our diluted EPS using the if-converted method.

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