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 May 2014, the FASB issued Accounting Standards Update (“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 below table summarizes the changes to our consolidated balance sheet as of December 31, 2018 as a result of the adoption of ASC 606:


	December 31, 2018		Adjustment for		December 31, 2018
	(Per ASC 605)		Adoption		(Per ASC 606)
	(in thousands)
Accounts receivable, net	$	43,410	$	(644)	$	42,766
Prepaid expenses and other current assets	$	7,603	$	212	$	7,815
Other assets	$	12,224	$	(2,288)	$	9,936
Deferred revenue, current	$	82,731	$	(2,348)	$	80,383
Deferred revenue, net of current portion	$	147,785	$	(10,580)	$	137,205
Non-controlling interests	$	408	$	1,803	$	2,211

The below table summarizes the changes to our consolidated statement of operations for the year ended December 31, 2018 as a result of the adoption of ASC 606 with income taxes calculated excluding the tax effect on the equity component of the Convertible Notes:


	Year Ended				Year Ended
	December 31, 2018		Adjustment for		December 31, 2018
	(Per ASC 605)		Adoption		(Per ASC 606)
	(in thousands)
Revenue	$	244,307	$	6,514	$	250,821
Income tax benefit	$	(4,785)	$	(368)	$	(5,153)
Non-controlling interests	$	(245)	$	1,734	$	1,489

The changes to the consolidated balance sheets as of January 1, 2018 and December 31, 2018 and the consolidated statement of operations for the year ended December 31, 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.

In May 2017, the FASB issued ASU 2017-09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting, which provides guidance on the types of changes to the terms or conditions of share-based payment awards to which an entity applies modification accounting under ASC 718. According to the new standard, an entity would not apply modification accounting if the fair value, vesting conditions and classification of the modified award is the same as the original award immediately before the original award is modified. The standard will be applied prospectively to modifications that occur on or after the adoption date. We adopted ASU 2017-09 on January 1, 2018 and the adoption of this standard did not have a material impact on our consolidated financial statements.

In January 2017, the FASB issued Accounting Standards Update (“ASU”) 2017-04, Intangibles-Goodwill and Other (Topic 350), which simplifies how an entity is required to test goodwill for impairment. An entity will no longer perform a hypothetical purchase price allocation to measure goodwill impairment. Instead, impairment will be measured using the difference between the carrying amount and the fair value of the reporting unit. The standard is effective for interim and annual periods beginning after December 15, 2019 with early adoption permitted for goodwill impairment tests with measurement dates after January 1, 2017. We elected to early adopt ASU 2017-04 as of January 1, 2017 and the adoption of this standard did not have a material impact on our consolidated financial statements.

In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash, which requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Therefore, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. We adopted ASU 2016-18 on January 1, 2018 under the retrospective transition method for each period presented in our consolidated statements of cash flows.

In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230), which adds or clarifies guidance to reduce diversity in how certain transactions are classified in the statement of cash flows. The standard is effective for interim and annual periods beginning after December 15, 2017 with early adoption permitted. The standard requires application using a retrospective transition method. We elected to early adopt ASU 2016-15 as of January 1, 2017 and the adoption of this standard did not have a material impact on our consolidated financial statements.

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, uncertain tax positions, useful lives associated with property and equipment, valuation and useful lives of intangible assets, valuation of contingent consideration, 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 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. For the year ended December 31, 2018, three customers accounted for 37% of total revenue. For the year ended December 31, 2017, four customers accounted for 44% of total revenue. For the year ended December 31, 2016, two customers accounted for 23% of total revenue. At December 31, 2018, four customers accounted for 20%, 19%, 17% and 13% of the total accounts receivable, respectively. At December 31, 2017, three customers accounted for 19%, 17% and 13% of the total accounts receivable, respectively.

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, 2018 and 2017, cash equivalents consisted of money market funds.

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 and cash equivalents, accounts receivable, prepaid expenses and other current assets, other assets, accounts payable, accrued expenses and other liabilities, and deferred revenue 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 is 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 18 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.

Equipment and software under capital lease

We lease certain data communications equipment, other equipment and software under capital lease agreements. The assets and liabilities under capital lease are recorded at the lesser of the present value of aggregate future minimum lease payments, including estimated bargain purchase options, or the fair value of the asset under lease. Assets under capital lease are depreciated using the straight‑line method over the estimated useful lives of the assets or the term of the lease agreements.

Software development costs

We capitalize costs associated with software developed or obtained for internal use when the preliminary project stage is completed, and it is determined that the software will provide significantly enhanced capabilities and modifications. These capitalized costs are included in property and equipment 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 projects. Capitalization of these costs ceases once the project is substantially complete and the software is ready for its intended use. Once the software is ready for its intended use, the costs are amortized over the useful life of the software. Post‑configuration training and maintenance costs are expensed as incurred.

Long‑lived assets

Intangible assets consist of acquired venue contracts, technology, advertiser relationships, non‑compete agreements 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.

Currently, we have one reporting unit, one operating segment and one reportable segment. At December 31, 2018 and 2017, all of the goodwill was attributed to our reporting unit. We tested our goodwill for impairment using a market-based approach and no impairment was identified as the fair value of our reporting unit was substantially in excess of its carrying amount. To date, we have not recorded any goodwill impairment charges.

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 bought 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) DAS customers that are telecom operators under long-term contracts for access to our DAS 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 to the residents and employees, (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.

Post-ASC 606 adoption

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, 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 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 ASC 606. 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 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 increases 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 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 wholesale Wi-Fi contracts that contain recurring fees with annual escalations are generally presented as contract assets as revenue is recognized prior to invoicing. Our multifamily 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 year ended December 31, 2018 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, the most significant of which relates to sales commissions related to obtaining our advertising customer contracts. Contract costs are evaluated for impairment in accordance with ASC 310, Receivables.

DAS

We enter into long-term contracts with telecom operators at our managed and operated locations. The initial term of our contracts with telecom operators generally range from five to twenty 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 customer contracts generally contain a single performance obligation—provide non-exclusive access to our DAS or 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 believe that a material right generally does not exist for our DAS 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 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 service provider. Our contracts also provide our DAS 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 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.

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 and small cell networks are 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 customer contract monthly over the contract term once the customer has the ability to access the DAS network and we commence maintenance on the DAS network.

Military and retail

Military and 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 and 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 and 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 and 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 and retail customers are paid monthly in advance. We provide refunds for our military and 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 and retail single-use access is recognized when access is provided, and the performance obligation is satisfied.

Multifamily

We enter into long-term contracts with property owners. The initial term of our contracts with property owners generally range from three to five 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. Our customer contracts 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 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.

Wholesale Wi-Fi

We enter into long-term contracts with enterprise customers such as telecom operators, 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. We also 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. The initial term of our contracts with wholesale Wi-Fi customers generally range from one to three 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 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. 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.

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 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.

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.

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.

Pre-ASC 606 adoption

We recognize revenue when an arrangement exists, services have been rendered, fees are fixed or determinable, no significant obligations remain related to the earned fees and collection of the related receivable is reasonably assured. Revenue is presented net of any sales and value added taxes.

Revenue generated from access to our DAS networks consists of build‑out fees and recurring access fees under certain long‑term contracts with telecom operators. Build‑out fees paid upfront are generally deferred and recognized ratably over the term of the estimated customer relationship period, once the build‑out is complete. Periodically, we install and sell Wi‑Fi and DAS 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. Minimum monthly access fees for usage of the DAS networks are non‑cancellable and generally escalate on an annual basis. These minimum monthly access fees are recognized ratably over the term of the telecom operator agreement. The initial term of our contracts with telecom operators generally range from five to twenty years and the agreements generally contain renewal clauses. Revenue from DAS network access fees in excess of the monthly minimums is recognized when earned.

Subscription fees from military and retail customers are paid monthly in advance and revenue is deferred for the portions of monthly recurring subscription fees collected in advance. We provide refunds for our military and retail services on a case-by-case basis. These amounts are not significant and are recorded as contra-revenue in the period the refunds are made. Subscription fee revenue is recognized ratably over the subscription period. Revenue generated from military and retail single-use access is recognized when access is provided.

Services provided to wholesale Wi‑Fi partners generally contain several elements including: (i) a term license to use our software to access our Wi‑Fi network, (ii) access fees for Wi‑Fi network usage, and/or (iii) professional services for software integration and customization and to maintain the Wi‑Fi service. The term license, monthly minimum network access fees and professional services are billed monthly based upon predetermined fixed rates. Once the term license for integration and customization are delivered, the fees from the arrangement are recognized ratably over the remaining term of the service arrangement. The initial term of the license agreements is generally between one to three years and the agreements generally contain renewal clauses. Revenue for Wi‑Fi network access fees in excess of the monthly minimum amounts is recognized when earned. All elements within existing service arrangements are generally delivered and earned concurrently throughout the term of the respective service arrangement.

In instances where the minimum monthly Wi‑Fi and DAS network access fees escalate over the term of the wholesale service arrangement, an unbilled receivable is recognized when performance is within our control and when we have reasonable assurance that the unbilled receivable balance will be collected.

We adopted the provisions of ASU 2009-13, Revenue Recognition (Topic 605)—Multiple-Deliverable Revenue Arrangements, on a prospective basis on January 1, 2011. For multiple-deliverable arrangements entered into prior to January 1, 2011 that are accounted for under ASC 605-25, Revenue Recognition—Multiple-Deliverable Revenue Arrangements, we defer recognition of revenue for the full arrangement and recognize all revenue ratably over the term of the estimated customer relationship period for DAS arrangements and the wholesale service period for Wi-Fi platform service arrangements, as we do not have evidence of fair value for the undelivered elements in the arrangement. For multiple-deliverable arrangements entered into or materially modified after January 1, 2011 that are accounted for under ASC 605-25, we evaluate whether separate units of accounting exist and then allocate the arrangement consideration to all units of accounting based on the relative selling price method using estimated selling prices if vendor specific objective evidence and third-party evidence is not available. We recognize the revenue associated with the separate units of accounting upon completion of such services or ratably over the term of the estimated customer relationship period for DAS arrangements and the wholesale service period for Wi-Fi platform service arrangements.

Advertising revenue is generated from advertisements on our managed and operated or partner networks. In determining whether an arrangement exists, we ensure that a binding arrangement is in place, such as a standard insertion order or a fully executed customer‑specific agreement. Obligations pursuant to our advertising revenue arrangements typically include a minimum number of units or the satisfaction of certain performance criteria. Advertising and other revenue is recognized when the services are performed.

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, 2018 and December 31, 2017, the Company had $(1,295) and $(898), respectively, of cumulative foreign currency translation adjustments, net of tax, which was $0 as of December 31, 2018 and December 31, 2017 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.

Network access

Network access costs 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, and bandwidth and other Internet connectivity expenses in our managed and operated locations.

Advertising, marketing and promotion costs

Advertising production costs are expensed the first time the advertisement is run. No advertising production costs were capitalized for the years ended December 31, 2018, 2017 and 2016. All other costs of advertising, marketing and promotion are expensed as incurred. Advertising expenses charged to operations totaled $2,213, $2,245 and $1,925 for the years ended December 31, 2018, 2017 and 2016, 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, 2018, 2017 and 2016, we made distributions of $614, $125 and $286, 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, 2018, 2017 and 2016, 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. Our common stockholders are not entitled to receive any dividends.

Segment and geographic information

We operate 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 is consistent with the internal organization structure and the manner in which operations are reviewed and managed by our Chief Executive Officer, the chief operating decision maker.

All significant long‑lived tangible assets are held in the United States of America. We do not disclose sales by geographic area because to do so would be impracticable.

The following is a summary of our revenue disaggregated by product offerings:


	Year Ended December 31,
	2018		2017 (1)		2016 (1)
Revenue:
DAS	$	95,216	$	80,552	$	58,182
Military/multifamily		77,721		55,129		39,975
Wholesale-Wi-Fi		47,481		31,529		22,221
Retail		17,630		24,926		26,636
Advertising and other		12,773		12,233		12,330
Total revenue	$	250,821	$	204,369	$	159,344

(1)

As noted above, prior period amounts have not been adjusted upon adoption of ASC 606 under the modified retrospective method.

Recent accounting pronouncements

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 are currently evaluating the expected impact of this new standard.

In June 2018, the FASB issued ASU 2018-07, Improvements to Nonemployee Share-Based Payment Accounting, which eliminates the separate accounting model for nonemployee share-based payment awards and generally requires companies to account for share-based payment transactions with nonemployees in the same way as share-based payment transactions with employees. The accounting remains different for attribution, which represents how the equity-based payment cost is recognized over the vesting period, and a contractual term election for valuing nonemployee equity share options. The standard is effective for interim and annual periods beginning after December 15, 2018. Early adoption is permitted for all entities on a modified retrospective basis. We currently do not expect that this standard will have a material impact on our consolidated financial statements.

In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842), which requires lessees to recognize assets and liabilities for all leases with lease terms of more than 12 months on the balance sheet. Under the new guidance, 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. The standard is effective for interim and annual periods beginning after December 15, 2018 with early adoption permitted. We have selected January 1, 2019 as our effective date. ASU 2016-02 provided for the adoption of the new leases standard using a modified retrospective transition method. In July 2018, the FASB issued ASU 2018-11, Leases (Topic 842): Targeted Improvements, which provided an additional (and optional) transition method to adopt the new leases standard whereby an entity initially applies the new leases standard at the adoption date and recognizes a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. We expect to adopt the provisions of ASU 842 under the optional transition method prescribed under ASU 2018-11. We are completing our evaluation of the impact of the new standard on our accounting policies, processes, and system requirements. We have assigned internal resources and engaged a third-party service provider to assist in the evaluation and implementation. Based on the lease portfolio as of December 31, 2018, we anticipate recording additional lease assets and lease liabilities on our consolidated balance sheets. As presented in Note 15, as of December 31, 2018, our total undiscounted minimum payments under our operating leases were $26,158.