Spok (SPOK) 10-Q26 Jul 182018 Q2 Quarterly reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2018	Jul. 20, 2018
Document Document And Entity Information [Abstract]
Entity Registrant Name	Spok Holdings, Inc
Entity Central Index Key	1,289,945
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding (shares)		19,458,125

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 94,068	$ 107,157
Accounts receivable, net	35,574	32,279
Prepaid expenses and other	7,050	5,752
Inventory	1,505	1,672
Total current assets	138,197	146,860
Non-current assets:
Property and equipment, net	13,035	13,399
Goodwill	133,031	133,031
Intangible assets, net	6,667	7,917
Deferred income tax assets	46,344	47,679
Other non-current assets	1,431	1,675
Total non-current assets	200,508	203,701
Total assets	338,705	350,561
Current liabilities:
Accounts payable	310	1,305
Accrued compensation and benefits	9,261	11,018
Accrued taxes	2,055	2,547
Deferred revenue	32,449	31,414
Other current liabilities	4,010	4,610
Total current liabilities	48,085	50,894
Non-current liabilities:
Deferred revenue	961	1,063
Other non-current liabilities	8,393	8,075
Total non-current liabilities	9,354	9,138
Total liabilities	57,439	60,032
Commitments and contingencies (Note 11)
Stockholders' equity:
Preferred stock	0	0
Common stock	2	2
Additional paid-in capital	92,102	99,819
Accumulated other comprehensive loss	(1,850)	(1,088)
Retained earnings	191,012	191,796
Total stockholders’ equity	281,266	290,529
Total liabilities and stockholders' equity	$ 338,705	$ 350,561

Condensed Consolidated Statemen

Condensed Consolidated Statement of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue:
Total revenue	$ 40,628	$ 42,325	$ 83,742	$ 83,769
Operating expenses:
Cost of revenue	7,400	7,190	15,133	14,226
Research and development	6,177	4,662	11,912	8,767
Service, rental and maintenance	7,698	7,944	15,448	16,010
Selling and marketing	6,093	5,329	12,562	11,251
General and administrative	12,741	11,939	24,704	23,649
Depreciation, amortization and accretion	2,669	2,851	5,382	6,074
Total operating expenses	42,778	39,915	85,141	79,977
Operating (loss) income	(2,150)	2,410	(1,399)	3,792
Interest income	342	154	625	276
Other income	102	89	54	58
(Loss) income before income taxes	(1,706)	2,653	(720)	4,126
Benefit from (provision for) income taxes	730	(1,155)	255	(1,774)
Net (loss) income	$ (976)	$ 1,498	$ (465)	$ 2,352
Basic net (loss) income per common share (usd per share)	$ (0.05)	$ 0.07	$ (0.02)	$ 0.12
Diluted net (loss) income per common share (usd per share)	$ (0.05)	$ 0.07	$ (0.02)	$ 0.11
Basic weighted average common shares outstanding (shares)	19,750,941	20,353,801	19,888,606	20,441,781
Diluted weighted average common shares outstanding (shares)	19,750,941	20,366,102	19,888,606	20,508,473
Cash dividends declared per common share (usd per share)	$ 0.125	$ 0.125	$ 0.25	$ 0.250
Wireless
Revenue:
Total revenue	$ 23,658	$ 25,639	$ 47,927	$ 51,499
Software
Revenue:
Total revenue	$ 16,970	$ 16,686	$ 35,815	$ 32,270

Condensed Consolidated Stateme4

Condensed Consolidated Statement of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (976)	$ 1,498	$ (465)	$ 2,352
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	(342)	82	(598)	86
Other comprehensive (loss) income	(342)	82	(598)	86
Comprehensive (loss) income	$ (1,318)	$ 1,580	$ (1,063)	$ 2,438

Condensed Consolidated Stateme5

Condensed Consolidated Statement of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows provided by operating activities:
Net (loss) income	$ (465)	$ 2,352
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion	5,382	6,074
Deferred income tax (benefit) expense	(472)	1,069
Stock based compensation	2,501	1,953
Provision for doubtful accounts, service credits and other	1,016	458
Adjustment of non-cash transaction taxes	(104)	(700)
Changes in assets and liabilities:
Accounts receivable	(2,986)	(1,242)
Prepaid expenses, inventory, and other assets	(277)	(2,684)
Accounts payable, accrued liabilities and other	(3,394)	(3,261)
Deferred revenue	5,191	2,561
Net cash provided by operating activities	6,392	6,580
Cash flows used in investing activities:
Purchase of property and equipment	(3,464)	(5,198)
Net cash used in investing activities	(3,464)	(5,198)
Cash flows used in financing activities:
Cash distributions to stockholders	(5,201)	(10,239)
Purchase of common stock for tax withholding on vested equity awards	(894)	0
Purchase of common stock (including commissions)	(9,467)	(10,024)
Proceeds from issuance of common stock under the Employee Stock Purchase Plan	143	130
Net cash used in financing activities	(15,419)	(20,133)
Effect of exchange rate on cash	(598)	86
Net decrease in cash and cash equivalents	(13,089)	(18,665)
Cash and cash equivalents, beginning of period	107,157	125,816
Cash and cash equivalents, end of period	94,068	107,151
Supplemental disclosure:
Income taxes paid	$ 457	$ 1,964

Organization and Significant Ac

Organization and Significant Accounting Policies	6 Months Ended
Organization and Significant Accounting Policies	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Significant Accounting Policies	ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES Spok Holdings, Inc. (NASDAQ: SPOK) ("Spok," "we," "our" or the "Company") through its wholly-owned subsidiary Spok, Inc., is the global leader in healthcare communications. We deliver clinical information to care teams when and where it matters most to improve patient outcomes. Many hospitals rely on the Spok Care Connect platform to enhance workflows for clinicians, support administrative compliance, and provide a better experience for patients. Our customers send over 100 million messages each month through their Spok solutions. We offer a focused suite of unified critical communication solutions that include call center operations, clinical alerting and notifications, one-way and advanced two-way wireless messaging services, mobile communications and public safety solutions. We provide one-way and advanced two-way wireless messaging services including information services throughout the United States. These services are offered on a local, regional and nationwide basis employing digital networks. One-way messaging consists of numeric and alphanumeric messaging services. Numeric messaging services enable subscribers to receive messages that are composed entirely of numbers, such as a phone number, while alphanumeric messages may include numbers and letters, which enable subscribers to receive text messages. Two-way messaging services enable subscribers to send and receive messages to and from other wireless messaging devices, including pagers, mobile devices and personal computers. We also offer voice mail, personalized greeting, message storage and retrieval, and equipment loss and/or maintenance protection to both one-way and two-way messaging subscribers. These services are commonly referred to as wireless messaging and information services. We also develop, sell and support enterprise-wide systems for hospitals and other organizations needing to automate, centralize and standardize mission critical communications. These solutions are used for contact centers, clinical alerting and notification, mobile communications and messaging and for public safety notifications. These areas of market focus complement the market focus of our wireless services outlined above. These products and services are commonly referred to as software solutions and services. Basis of Presentation The accompanying Condensed Consolidated Financial Statements include our accounts and the accounts of our wholly-owned direct and indirect subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. Our Condensed Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) and the rules and regulations of the United States Securities and Exchange Commission (the “SEC”). In management's opinion, the unaudited Condensed Consolidated Financial Statements include all adjustments and accruals that are necessary for a fair presentation of the results of all interim periods reported herein and all such adjustments are of a normal, recurring nature. As a result of the adoption of Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers , and our application of the modified retrospective approach, prior period amounts have not been restated under ASC 606. Amounts shown on the Condensed Consolidated Statement of Operations within the operating expense categories of Cost of revenue; Research and development; Service, rental and maintenance; Selling and marketing; and General and administrative are recorded exclusive of depreciation, amortization and accretion. The financial information included herein, other than the Condensed Consolidated Balance Sheet as of December 31, 2017 , is unaudited. The Condensed Consolidated Balance Sheet at December 31, 2017 has been derived from, but does not include all, the disclosures contained in the audited Consolidated Financial Statements as of and for the year ended December 31, 2017 . These Condensed Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and accompanying notes included in the Company's Annual Report on Form 10-K for the year ended December 31, 2017 (the “ 2017 Annual Report”). The Condensed Consolidated Statement of Operations for the interim periods presented are not necessarily indicative of the results that may be expected for a full year. Certain prior period amounts in the Condensed Consolidated Financial Statements have been reclassified to conform to the current period's presentation. These reclassifications had no effect on the reported results of operations or the statement of financial position. In the first quarter of 2018, the Company reclassified ($1.5) million from additional paid-in capital to accumulated other comprehensive income. Corresponding reclassifications of ($1.1) million were made to the Condensed Consolidated Balance Sheets for the year ended December 31, 2017. Use of Estimates The preparation of these Condensed Consolidated Financial Statements requires management to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues, expenses and related disclosures. On an on-going basis, we evaluate estimates and assumptions, including, but not limited to, those related to the impairment of long-lived assets; intangible assets subject to amortization and goodwill; accounts receivable allowances; revenue recognition; determining standalone selling price ("SSP") of performance obligations; variable consideration; depreciation expense; asset retirement obligations; severance and income taxes. We base our estimates on historical experience and various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.

Risks and Other Important Facto

Risks and Other Important Factors	6 Months Ended
Risks and Other Important Factors	Jun. 30, 2018
Risks and Uncertainties [Abstract]
Risks and Other Important Factors	RISKS AND OTHER IMPORTANT FACTORS See “Item 1A. Risk Factors” of Part II of this Quarterly Report on Form 10-Q (“Quarterly Report”) and "Item 1A. Risk Factors" of Part I of the 2017 Annual Report, which describe key risks associated with our operations and industry.

Recent and Pending Accounting S

Recent and Pending Accounting Standards	6 Months Ended
Recent and Pending Accounting Standards	Jun. 30, 2018
Accounting Changes and Error Corrections [Abstract]
Recent and Pending Accounting Standards	RECENT AND PENDING ACCOUNTING STANDARDS Recently Adopted Revenue - In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers . ASU No. 2014-09 creates a five-step model that requires companies to exercise judgment when considering all relevant facts and circumstances in the determination of when and how revenue is recognized and requires entities to recognize revenues when control of the promised goods or services is transferred to customers at an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. 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. As a result, our beginning retained earnings as of January 1, 2018 was $6.4 million greater than what was reported at December 31, 2017. This was due to a $4.2 million decrease in deferred revenue, a $0.2 million decrease in accumulated other comprehensive income related to translation adjustments, an increase in unbilled receivables of $1.3 million and an increase of $0.7 million in deferred commissions that resulted from the adoption of ASC 606. Results for reporting periods beginning after January 1, 2018 are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported in accordance with our historic accounting under ASC 605. For additional details refer to Note 4 , "Significant Accounting Policies Update" and Note 5 , "Revenues." Pending Adoption Leases - In February 2016, the FASB issued ASU No. 2016-02, Leases . The new standard establishes a right of use (“ROU”) model that requires a lessee to record a ROU asset and a lease liability on the balance sheet for all leases with terms longer than twelve months. Leases will be classified as either financing or operating with the classification affecting the pattern of expense recognition in the Condensed Consolidated Statement of Operations. ASU No. 2016-02 will be effective beginning on January 1, 2019, including interim periods within that fiscal year, and while early adoption is permitted, we have elected not to early adopt. A modified retrospective transition approach is required for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the Condensed Consolidated Financial Statements, with certain practical expedients available. While we are still evaluating the impact of the potential new standard on our consolidated Financial Statements, we expect that upon adoption we will recognize ROU assets and lease liabilities and that the amounts could be material. We do not anticipate a material change in how our lease expense is recognized in future Consolidated Statements of Operations as a result of the adoption of ASU No. 2016-02.

Significant Accounting Policies

Significant Accounting Policies Update	6 Months Ended
Significant Accounting Policies Update	Jun. 30, 2018
Accounting Policies [Abstract]
Significant Accounting Policies Update	SIGNIFICANT ACCOUNTING POLICIES UPDATE Our significant accounting policies are detailed in Note 1 “Organization and Significant Accounting Policies” of our Annual Report on Form 10-K for the year ended December 31, 2017. Significant changes to our accounting policies as a result of adopting ASC 606 are discussed below. Revenue Recognition - Adoption of ASC 606 “Revenue from Contracts with Customers” The majority of our revenues are derived from short-term contracts related to the sale of wireless paging services and software solutions. Our arrangements exist primarily with customers in the healthcare market and to a lesser extent State and Federal governments, as well as large enterprise businesses. Under the typical payment terms of our software contracts customers will normally pay a material amount of the contract price immediately upon execution of the contract. The remaining payments are required when product is delivered, when services begin and, to a lesser extent, when services are completed. Wireless services are generally billed as incurred on a monthly basis. Our contracts will generally result in billings in excess of revenue recognized, which we present as deferred revenues on the Condensed Consolidated Balance Sheets, primarily due to the receipt of payment in advance of product or services being provided. Amounts billed and due from our customers are classified as receivables on the Condensed Consolidated Balance Sheets. At times, we may have contracts which require us to perform work or provide products prior to billing which will generally result in revenue recognized in excess of billings. This excess is presented as unbilled receivables in the Notes to the Condensed Consolidated Balance Sheets. We generally do not have transactions that include a significant financing component (whether payments are made in advance or in arrears) as our contracts typically take less than 12 months to complete once started. We would not adjust the total consideration for the effects of a significant financing component if we anticipate, at contract inception, that the period between when we transfer a promised good or service to a customer and when the customer pays for that good or service will be one year or less. We account for a contract when: (1) both parties have approved the contract through mutually signed agreements but at times may be done through other methods such as purchase orders or master agreements; (2) the rights of the parties have been identified; (3) payment terms have been identified; (4) the contract has commercial substance; and (5) collectability of consideration is probable. We also evaluate whether two or more contracts should be combined and accounted for as a single contract. In our evaluation, we consider criteria such as, but not limited to, whether: (1) the contracts are negotiated as a package with a single commercial objective; (2) the amount of consideration to be paid in one contract is dependent on the price or performance of another contract; and (3) some or all of the goods or services promised in the contracts are a single performance obligation. Should we consider contracts related, we would account for those contracts as if they were a single contract. Evaluating whether two or more contracts should be combined and accounted for as a single contract requires significant judgment. In the aggregate, a decision to combine a group of contracts could significantly impact the amount of revenue and profit recorded in a given period. We review each contract to determine whether to account for the various promises as one or more performance obligations. The assessment and determination of performance obligations for a given contract requires significant judgment. Contracts which include wireless services are generally considered to be a single promise and therefore accounted for as a single performance obligation. Less commonly, however, we may promise to provide other distinct goods or services in conjunction with wireless services in which case we would account for the contract as having multiple performance obligations. Contracts which include goods or services related to our software solutions are generally sold with multiple promises and therefore will often include multiple performance obligations. Material performance obligations related to the sale of our software solutions include software licenses, professional services, hardware and maintenance, of which professional services and maintenance are generally considered a series of performance obligations. More often than not, total consideration will equate to the stated value on the contract taking into consideration any period or term over which services are to be provided, if applicable. However, we could have contracts in which variable consideration is present. It is common for our contracts which include wireless services to contain customer penalties if rental pagers are not returned and fees for usage of services in excess of the contractually allotted amount for a given period. It is also common for our contracts that include professional services to include travel related costs. These are costs which we incur in the normal course of delivering professional services and are generally billable to the customer based on our incurred expenses. These elements of variable consideration are fully constrained when an agreement is initially executed and are generally not considered estimable until the penalties, fees or costs have been incurred or are otherwise known. We include estimated amounts in the transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved. Estimating variable consideration requires significant judgment and our assessment includes all relevant information that is reasonably available to us including historical, current and forecasted information. We have elected to exclude from revenue, all amounts collected on behalf of third parties, and therefore, items such as sales and use tax are excluded from our calculation of the total transaction price. If a contract is separated into more than one performance obligation we allocate the total transaction price to each performance obligation proportionately based on the estimated relative SSPs of the promised goods or services underlying each performance obligation. We rarely sell goods or services with readily observable standalone sales, however, if we do, the observable standalone sales are used to determine the SSP. In most cases, we must estimate the relative SSP which requires significant judgment and estimates. In instances where SSP is not directly observable we determine the SSP using information that may include contractually stated prices, market conditions, costs, renewal contracts, list prices and other observable inputs. A discount is present if the total transaction price is less than the sum of the estimated SSPs of the goods or services promised in the contract. Discounts are generally allocated proportionately based on the relative SSP of the identified performance obligations for a given contract. Our wireless, professional and maintenance services are generally recognized over time due to a customer's simultaneous receipt and consumption of the benefit as we perform the work. As we transfer control over time, we recognize revenue based on the extent of progress towards completion of the performance obligation. The selection of the method to measure progress towards completion requires significant judgment and is based on the nature of the products or services to be provided. Generally, we use the time-elapsed measure of progress for performance obligations which include wireless or maintenance services. We believe this method best depicts the simultaneous transfer and consumption of the benefit based on our performance as these services are generally considered standby services. For professional services, we leverage an input methodology based on the number of hours worked on a project versus the total expected hours necessary to complete the project. Revenues are recognized proportionally as hours are incurred. This is a significant area of judgment as it requires an estimate to complete (“ETC”) for each contract. Our initial ETC is primarily based on prior experience also taking into consideration any specific facts and circumstances for a given contract. As projects progress, the ETC is periodically updated and reviewed to ensure the timing of revenue recognition is appropriate. The creation, maintenance and review of a projects ETC requires significant judgment to determine an appropriate number of hours over which the remaining project is expected to be completed. Our software licenses and hardware are generally recognized at a point in time when we have transferred control to the customer. For software licenses, revenue is not recognized until the related license(s) has been made available to the customer and the customer can begin to benefit from its right to use the license(s). Our software licenses represent a right to use Spok’s Intellectual Property (“IP”) as it exists at a point in time at which the license is granted. Many of our software licenses have significant standalone functionality due to their ability to process a transaction or perform a function or task, and we do not need to maintain those products, once provided to the customer, for value to exist. While the functionality of IP that we license may substantively change during the license period, customers are not contractually or practically required to update their license as a result of those changes. Assessing when transfer of control has occurred requires significant judgment. In most contracts transfer of control for software licenses occurs in a short period of time after a contract has been executed and licenses are made electronically available. Contracts may be modified to account for changes in a project's scope or other customer requirements. Most of our contract modifications are for goods or services that are distinct from the existing contract or may or may not be distinct but are for services which relate to a series of performance obligations. In these instances, the contract modification would either be recognized as an entirely new and separate contract or the modification would be treated as if it were a termination of the existing contract and the creation of a new contract including all untransferred goods and services under the previous contract. Revenue would be recognized on a prospective basis and a cumulative catch-up would not be recognized. Incremental costs of obtaining a contract and costs to fulfill a contract Commissions Expense - Our incremental costs primarily relate to sales commissions. We capitalize commissions and proportionally recognize the related expense to revenue as it is recognized on the underlying performance obligations. Some of these costs may relate to specific future anticipated contracts, specifically future maintenance renewals, which we do not pay commensurate sales commissions on. We amortize commission costs proportionally with revenue, thus it is necessary for us to estimate future revenues when there are future anticipated contracts. We estimate future revenues based on anticipated renewal amounts over an expected useful life (e.g. the period over which we believe the initial sales commissions relate to future anticipated contracts). The expected useful life is based on a review of our product life cycles, customer upgrade patterns and the rate at which customers renew maintenance. Commissions expenses are classified as Selling and Marketing on the Condensed Consolidated Statement of Operations. Summary of Results under ASC 605 “Revenue Recognition” The following table presents Financial Statement components impacted as a result of adopting ASC 606, stated under ASC 605 for comparative purposes: For the Three Months Ended June 30, For the Six Months Ended June 30, 2018 2017 2018 2017 (Dollars in thousands) ASC 606 ASC 605 ASC 605 ASC 606 ASC 605 ASC 605 Condensed Consolidated Statement of Operations Revenues: Software $ 16,970 $ 18,136 $ 16,686 $ 35,815 $ 36,324 $ 32,270 Operating expenses: Selling and marketing $ 6,093 $ 6,198 $ 5,329 $ 12,562 $ 12,228 $ 11,251 Condensed Consolidated Statement of Comprehensive Income Other comprehensive (loss) income, net of tax: $ (342 ) $ (308 ) $ 82 $ (598 ) $ (472 ) $ 86 June 30, 2018 December 31, 2017 (Dollars in thousands) ASC 606 ASC 605 ASC 605 Condensed Consolidated Balance Sheets Current assets: Accounts receivable, net $ 35,574 $ 33,010 $ 32,279 Current assets: Prepaid expenses and other $ 7,050 $ 6,710 $ 5,752 Current liabilities: Deferred revenue $ 32,449 $ 34,667 $ 31,414 Non-current liabilities: Deferred revenue $ 961 $ 1,176 $ 1,063 Stockholder equity: Accumulated other comprehensive loss $ (1,850 ) $ (1,604 ) $ (1,088 ) Stockholder equity: Retained earnings $ 191,012 $ 185,429 $ 191,796

Revenue, Deferred Revenue And D

Revenue, Deferred Revenue And Deferred Commissions	6 Months Ended
Revenue, Deferred Revenue And Deferred Commissions	Jun. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue, Deferred Revenue and Deferred Commissions	REVENUE, DEFERRED REVENUE AND DEFERRED COMMISSIONS Wireless Revenue Wireless revenue consists of two primary components: Paging revenue and product and other revenue. Paging revenue consists primarily of recurring fees associated with the provision of messaging services and fees for paging devices and is net of a provision for service credits. Product and other revenue reflects system sales, the sale of devices and charges for paging devices that are not returned and are net of anticipated credits. Our core offering includes subscriptions to one-way or two-way messaging services for a periodic (monthly, quarterly, semiannual, or annual) service fee. This is generally based upon the type of service provided, the geographic area covered, the number of devices provided to the customer and the period of commitment. A subscriber to one-way messaging services may select coverage on a local, regional or nationwide basis to best meet their messaging needs. Two-way messaging is generally offered on a nationwide basis. In addition, subscribers either contract for a messaging device from us for an additional fixed monthly fee or they own a device, having purchased it either from us or from another vendor. We also sell devices to resellers who lease or resell devices to their subscribers and then sell messaging services utilizing our networks. We offer ancillary services, such as voicemail and equipment loss or maintenance protection, which help increase the monthly recurring revenue we receive along with these traditional messaging services. In 2015 and 2016 we launched new and exclusive one-way (T5) and two-way (T52) alphanumeric pagers, respectively. Both pagers are configurable to support un-encrypted or encrypted operation. When configured for encryption, they utilize AES-128 bit encryption, screen locking and remote wipe capabilities. With encryption enabled these new secure paging devices enhance our service offerings to the healthcare community by adding Health Insurance Portability and Accountability Act ("HIPAA") security capabilities to the low cost, highly reliable and availability benefits of paging. (See Item 1. “Business,” in the 2017 Annual Report for more details.) Software Revenue Software revenue consists of two primary components: operations revenue and maintenance revenue. Operations revenue consists primarily of license revenues for our healthcare communications solutions, equipment revenues that facilitate the use of our software solutions, and professional services revenue related to the implementation of our solutions. Maintenance revenue is for ongoing support of our software solutions or related equipment (typically for one year). Our software licenses and hardware are generally recognized at a point in time when we have transferred control to the customer. For software licenses, revenue is not recognized until the related license(s) has been made available to the customer and the customer can begin to benefit from its right to use the license(s). Our software licenses represent a right to use Spok’s IP as it exists at a point in time at which the license is granted. Many of our software licenses have significant standalone functionality due to their ability to process a transaction or perform a function or task, and we do not need to maintain those products, once provided to the customer, for value to exist. While the functionality of IP that we license may substantively change during the license period, customers are not contractually or practically required to update their license as a result of those changes. Our wireless, professional and maintenance services are generally recognized over time due to a customer's simultaneous receipt and consumption of the benefit as we perform the work. As we transfer control over time, we recognize revenue based on the extent of progress towards completion of the performance obligation. The selection of the method to measure progress towards completion requires significant judgment and is based on the nature of the products or services to be provided. Generally, we use the time-elapsed measure of progress for performance obligations which include wireless or maintenance services. We believe this method best depicts the simultaneous transfer and consumption of the benefit based on our performance as these services are generally considered standby services. For professional services, we leverage an input methodology based on the number of hours worked on a project versus the total expected hours necessary to complete the project. Revenues are recognized proportionally as hours are incurred. Revenue Recognition Revenues are recognized when 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. The following table presents our revenues disaggregated by revenue type: For the Three months ended June 30, For the Six Months Ended June 30, (Dollars in thousands) 2018 2017 (1) 2018 2017 (1) Wireless products and services $ 23,658 $ 25,639 $ 47,927 $ 51,499 Subscription 441 623 861 1,167 Software licenses 1,552 1,641 5,508 2,812 Professional services 4,363 3,650 8,433 7,003 Hardware 1,107 1,127 2,132 2,100 Maintenance 9,507 9,645 18,881 19,188 Total revenue $ 40,628 $ 42,325 $ 83,742 $ 83,769 (1) Prior period amounts have not been adjusted under the modified retrospective method for the adoption of ASC 606. The U.S. was the only country that accounted for more than 10% of the Company’s total revenue for the three and six ended June 30, 2018 and 2017 Revenue by geographic region consisted of the following for the periods stated: For the Three months ended June 30, For the Six Months Ended June 30, (Dollars in thousands) 2018 2017 (1) 2018 2017 (1) Revenue United States $ 39,109 $ 40,869 $ 81,044 $ 81,374 International 1,519 1,456 2,698 2,395 Total revenue $ 40,628 $ 42,325 $ 83,742 $ 83,769 (1) Prior period amounts have not been adjusted under the modified retrospective method for the adoption of ASC 606. Deferred Revenues Our deferred revenues represent payments made to, or due from, customers in advance of our performance. Changes in the balance of total deferred revenue during the six months ended June 30, 2018 are as follows: (Dollars in thousands) December 31, 2017 Additions Revenue Recognized(1) June 30, 2018 Deferred Revenue $ 32,477 $ 30,976 $ (30,043 ) $ 33,410 (1) Includes $4.2 million which went to retained earnings and was not recognized as revenue resulting from the adoption of ASC 606. During the six months ended June 30, 2018, the Company recognized $16.5 million related to amounts deferred as of December 31, 2017. Deferred Commissions Our deferred commissions represent payments made to employees in advance of our performance on the related underlying contracts. These costs have been incurred directly in relation with obtaining a contract. As such, these costs are amortized over the estimated period of benefit. Changes in the balance of total deferred commissions during the six months ended June 30, 2018 are as follows: (Dollars in thousands) December 31, 2017 Additions (1) Commissions Recognized June 30, 2018 Deferred Commissions $ 1,676 $ 3,647 $ (3,168 ) $ 2,155 (1) Includes $0.7 million in previously recognized commissions expense which was removed from retained earnings and included in deferred commissions resulting from the adoption of ASC 606. Deferred commissions are included within prepaid assets on the Condensed Consolidated Balance Sheets and commissions expense is included within Selling and marketing on the Condensed Consolidated Statement of Operations. Remaining Performance Obligations We have elected not to disclose the value of unsatisfied performance obligations for contracts with an original expected length of one year or less and for variable consideration which is allocated entirely to a wholly unsatisfied performance obligation or to a wholly unsatisfied promise to transfer a distinct good or service that forms part of a single performance obligation. The remaining backlog is immaterial to our Condensed Consolidated Financial Statements.

Consolidated Financial Statemen

Consolidated Financial Statement Components	6 Months Ended
Consolidated Financial Statement Components	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Consolidated Financial Statement Components	CONSOLIDATED FINANCIAL STATEMENT COMPONENTS Depreciation, Amortization and Accretion Depreciation, amortization and accretion expenses consisted of the following for the periods stated: For the Three Months Ended June 30, For the Six Months Ended June 30, (Dollars in thousands) 2018 2017 2018 2017 Depreciation Leasehold improvements $ 67 $ 75 $ 135 $ 125 Asset retirement costs (76 ) (97 ) (152 ) (195 ) Paging and computer equipment 1,815 2,028 3,670 4,087 Furniture, fixtures and vehicles 103 76 209 141 Total depreciation 1,909 2,082 3,862 4,158 Amortization 625 629 1,250 1,636 Accretion 135 140 270 280 Total depreciation, amortization and accretion expense $ 2,669 $ 2,851 $ 5,382 $ 6,074 Accounts Receivable, Net Accounts receivable was recorded net of an allowance of $ 1.5 million and $1.1 million at June 30, 2018 and December 31, 2017 , respectively. Accounts receivable, net includes $10.1 million and $7.3 million of unbilled receivables at June 30, 2018 and December 31, 2017 , respectively. Unbilled receivables are defined as the Company's right to consideration in exchange for goods or services that we have transferred to the customer but have not yet billed for, generally as a result of contractual billing terms. The increase in unbilled receivables was primarily due to the adoption of ASC 606 and the acceleration of license revenue for the six months ended June 30, 2018 . Property and Equipment, Net Property and equipment, net consisted of the following as of the date stated: (Dollars in thousands) Useful Life June 30, 2018 December 31, 2017 Leasehold improvements shorter of useful life or lease term $ 4,135 $ 4,107 Asset retirement costs 1-5 3,267 3,228 Paging and computer equipment 1-5 101,526 103,520 Furniture, fixtures and vehicles 3-5 5,345 4,545 Total property and equipment 114,273 115,400 Accumulated depreciation (101,238 ) (102,001 ) Total property and equipment, net $ 13,035 $ 13,399 Other Current Liabilities Other current liabilities consisted of the following as of the date stated: (Dollars in thousands) June 30, 2018 December 31, 2017 Accrued network costs, asset retirement obligations and other $ 2,496 $ 2,173 Accrued outside services 1,514 2,437 Total other current liabilities $ 4,010 $ 4,610 Other Non-Current Liabilities Other non-current liabilities consisted of the following as of the date stated: (Dollars in thousands) June 30, 2018 December 31, 2017 Asset retirement obligations $ 7,351 $ 7,174 Other 1,042 901 Total other non-current liabilities $ 8,393 $ 8,075

Intangible Assets, Net

Intangible Assets, Net	6 Months Ended
Intangible Assets, Net	Jun. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets, Net	INTANGIBLE ASSETS, NET Intangible Assets Amortizable intangible assets at June 30, 2018 related primarily to customer relationships that resulted from our acquisition of Amcom Software, Inc. in 2011. Such intangibles are being amortized over a period of ten years . The net consolidated balance of intangible assets consisted of the following at June 30, 2018 : June 30, 2018 (Dollars in thousands) Useful Life Gross Carrying Accumulated Net Balance Customer relationships 10 $ 25,002 $ (18,335 ) $ 6,667 Total amortizable intangible assets $ 25,002 $ (18,335 ) $ 6,667 Estimated amortization of intangible assets for future periods was as follows: (Dollars in thousands) For the remaining six months ending December 31, 2018 $ 1,250 For the year ending December 31: 2019 2,500 2020 2,500 2021 417 Total amortizable intangible assets $ 6,667

Asset Retirement Obligations

Asset Retirement Obligations	6 Months Ended
Asset Retirement Obligations	Jun. 30, 2018
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	ASSET RETIREMENT OBLIGATIONS The components of the changes in the asset retirement obligation liabilities were: (Dollars in thousands) Short-Term Long-Term Total Balance at January 1, 2018 $ 235 $ 7,174 $ 7,409 Accretion (45 ) 315 270 Amounts paid (83 ) — (83 ) Increases — 39 39 Reclassifications 177 (177 ) — Balance at June 30, 2018 $ 284 $ 7,351 $ 7,635 The balances above were included within other current liabilities and other non-current liabilities on the Condensed Consolidated Balance Sheet, respectively, at June 30, 2018 . Increases other than accretion, reclassification and amounts paid primarily relate to changes in estimate of the underlying liability, specifically as it relates to updates in estimated costs to remove a transmitter and the estimated timing of removal. The cost associated with the estimated removal costs and timing refinements due to ongoing network rationalization activities is expected to accrete to a total liability of $9.0 million . The total estimated liability is based on the transmitter locations remaining after we have consolidated the number of networks we operate and assume the underlying leases continue to be renewed to that future date. Accretion expense was $0.3 million for the six months ended June 30, 2018 and 2017 . Accretion expense related solely to asset retirement obligations and was recorded based on the interest method.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
Stockholders' Equity	Jun. 30, 2018
Equity [Abstract]
Stockholders' Equity	STOCKHOLDERS' EQUITY General Our authorized capital stock consists of 75 million shares of common stock, par value $0.0001 per share, and 25 million shares of preferred stock, par value $0.0001 per share. At June 30, 2018 and December 31, 2017 , we had no stock options outstanding. At June 30, 2018 and December 31, 2017 , there were 19,472,249 and 20,135,514 shares of common stock outstanding, respectively, and no shares of preferred stock outstanding. Changes in Stockholders' Equity Changes in stockholders’ equity for the six months ended June 30, 2018 consisted of the following: (Dollars in thousands) Balance at January 1, 2018 $ 290,529 Adjustment to beginning balance resulting from adoption of ASC 606 6,258 Net loss for the six months, ended June 30, 2018 (465 ) Estimated tax impact resulting from adoption of ASC 606 (1,614 ) Cash dividends declared (5,127 ) Common stock repurchase program (9,467 ) Amortization of stock based compensation 2,501 Repurchase of common stock for tax withholdings (894 ) Cumulative translation adjustment (598 ) Issuance of common stock under the Employee Stock Purchase Plan 143 Balance at June 30, 2018 $ 281,266 Dividends The following table details our cash dividends declared in 2018 . Cash dividends paid as disclosed in the Condensed Consolidated Statement of Cash Flows for the six months ended June 30, 2018 and 2017 include previously declared cash dividends on shares of vested restricted common stock ("restricted stock") issued to our non-executive directors and dividends related to vested restricted stock units ("RSUs") issued to eligible employees. Cash dividends on RSUs and restricted stock have been accrued and are paid when the applicable vesting conditions are met. Accrued cash dividends on forfeited restricted stock and RSUs are also forfeited. Declaration Date Record Date Payment Date Per Share Amount Total Declared (1) (Dollars in thousands) February 28, 2018 March 16, 2018 March 30, 2018 $ 0.125 $ 2,589 April 25, 2018 May 25, 2018 June 22, 2018 0.125 2,538 Total $ 0.250 $ 5,127 (1) The total declared reflects the cash dividends declared in relation to common stock and unvested RSUs. On July 25, 2018, our Board of Directors declared a regular quarterly cash dividend of $0.125 per share of common stock with a record date of August 17, 2018, and a payment date of September 10, 2018. This cash dividend of approximately $2.4 million will be paid from available cash on hand. Common Stock Repurchase Program On February 28, 2018, the Company's Board of Directors authorized the repurchase of up to $10.0 million of the Company's common stock through 2018 on the open market or in privately negotiated transactions. The following table presents information with respect to purchases made by the Company during the six months ended June 30, 2018 : Period Total Number of Shares Purchased Average Price Paid Per Share (1) Total Number of Shares Purchased as Part of Publicly Announced Plans or Programs Approximate Dollar Value of Shares That May Yet Be Purchased Under the Plans or Programs (Dollars in thousands) Three Months Ended March 31, 2018 127,792 $ 15.04 127,792 $ 8,077 Three Months Ended June 30, 2018 501,782 14.99 501,782 $ 558 Total 629,574 $ 15.00 629,574 (1) Average price paid per share excludes commissions of approximately $25,183 . The above table excludes shares repurchased to settle employee tax withholding related to the vesting of equity awards. Net (Loss) Income per Common Share Basic net (loss) income per common share is computed on the basis of the weighted average common shares outstanding. Diluted net (loss) income per common share is computed on the basis of the weighted average common shares outstanding plus the effect of all potentially dilutive common shares including outstanding restricted stock and RSUs, which are treated as contingently issuable shares, using the “treasury stock” method. The components of basic and diluted net (loss) income per common share were as follows for the periods stated: For the Three Months Ended June 30, For the Six Months Ended June 30, (in thousands, except for share and per share amounts) 2018 2017 2018 2017 Numerator: Net (loss) income $ (976 ) $ 1,498 $ (465 ) $ 2,352 Denominator: Basic weighted average outstanding shares of common stock 19,750,941 20,353,801 19,888,606 20,441,781 Diluted weighted average outstanding shares of common stock 19,750,941 20,366,102 19,888,606 20,508,473 Basic net (loss) income per common share $ (0.05 ) $ 0.07 $ (0.02 ) $ 0.12 Diluted net (loss) income per common share $ (0.05 ) $ 0.07 $ (0.02 ) $ 0.11 For the three and six months ended June 30, 2018 and 2017 the following securities were excluded from the calculation of diluted shares outstanding as the effect would have been anti-dilutive: For the Three Months Ended June 30, For the Six Months Ended June 30, 2018 2017 2018 2017 Restricted stock units $ 77,190 $ — $ 145,526 $ — Share-Based Compensation Plans On March 23, 2012, our Board of Directors adopted the Spok Holdings, Inc. 2012 Equity Incentive Award Plan (the “2012 Equity Plan”) that was subsequently approved by our stockholders on May 16, 2012. A total of 2,194,986 shares of common stock have been reserved for issuance under this plan. Awards under the 2012 Equity Plan may be in the form of stock options, common stock, restricted stock, RSUs, performance awards, dividend equivalents, deferred stock, deferred stock units, or stock appreciation rights. Restricted stock awards generally vest one year from the date of grant. Related dividends accumulate during the vesting period and are paid at the time of vesting. Contingent RSUs generally vest over a three year performance period upon successful completion of the performance objectives. Non-contingent RSUs generally vest in thirds, annually, over a three year period. Dividend equivalents rights generally accompany each RSU award and those rights accumulate and vest along with the underlying RSU. The following table summarizes the activities under the 2012 Equity Incentive Award Plan ("2012 Equity Plan") from January 1, 2018 through June 30, 2018 : Activity Total equity securities available at January 1, 2018 1,140,658 RSU and restricted stock awarded to eligible employees, net of forfeitures (337,640 ) Total equity securities available at June 30, 2018 803,018 The following table details activities with respect to outstanding RSUs and restricted stock for the six months ended June 30, 2018 : Shares Weighted- Unvested at January 1, 2018 (1) 393,084 $ 18.54 Granted 334,035 16.47 Vested — — Forfeited (8,489 ) 17.72 Unvested at June 30, 2018 (1) 718,630 $ 17.59 (1) Approximately 99,451 RSUs from the 2016 grant are not expected to vest based on the Company's current assessment of the related performance obligations. Of the 718,630 unvested RSUs and restricted stock outstanding at June 30, 2018 , 362,974 RSUs include contingent performance requirements for vesting purposes. At June 30, 2018 , there was $5.9 million of unrecognized net compensation cost related to RSUs and restricted stock, which is expected to be recognized over a weighted average period of 1.86 years. Employee Stock Purchase Plan. In 2016 our Board of Directors adopted the Spok Holdings, Inc. Employee Stock Purchase Plan ("ESPP") that was subsequently approved by our stockholders on July 25, 2016. A total of 250,000 shares of common stock have been reserved for issuance under this plan. The Company's ESPP allows employees to purchase shares of common stock at a discounted rate, subject to plan limitations. Under the ESPP, eligible participants can voluntarily elect to have contributions withheld from their pay for the duration of an offering period, subject to the ESPP limits. At the end of an offering period, contributions will be used to purchase the Company's common stock at a discount to the market price based on the first or last day of the offering period, whichever is lower. Participants are required to hold common stock for a minimum period of two years from the grant date. Participants will begin earning dividends on shares after the purchase date. Each offering period will generally last for no longer than six months. Once an offering period begins, participants cannot adjust their withholding amount. If a participant chooses to withdraw, any previously withheld funds will be returned to the participant, with no stock purchased, and that participant will be eligible to participate in the ESPP at the next offering period. If the participant terminates employment with the Company during the offering period, all contributions will be returned to the employee and no stock will be purchased at a discounted rate. The Company uses the Black-Scholes model to calculate the fair value of the common stock to be purchased each offering period on their offer date. The Black-Scholes model requires the use of estimates for the expected term, the expected volatility of the underlying common stock over the expected term, the risk-free interest rate and the expected dividend payment. For the three and six months ended June 30, 2018 and 2017, 11,581 and 8,983 shares of the Company's common stock were purchased, respectively, for a total cost of $0.1 million . The following table summarizes the activities under the ESPP from January 1, 2018 through June 30, 2018 : Activity Total ESPP equity securities available at January 1, 2018 228,279 ESPP common stock purchased by eligible employees (11,581 ) Total ESPP securities available at June 30, 2018 216,698 Amounts withheld from participants will be classified an accrued compensation and benefit on the Condensed Consolidated Balance Sheets until funds are used to purchase shares. This liability amount is immaterial to the Condensed Consolidated Financial Statements. Stock-Based Compensation Expense We record all stock-based awards, which consist of RSUs, restricted stock and the option to purchase common stock under the ESPP, at fair value as of the grant date. Stock based compensation expense is recognized based on a straight-line amortization basis over the respective service period. Forfeitures and withdrawals are accounted for as incurred. The following table reflects the items for stock based compensation expense on the Condensed Consolidated Statement of Operations for the periods stated: For the Three Months Ended June 30, For the Six Months Ended June 30, (Dollars in thousands) 2018 2017 2018 2017 Performance-based RSUs $ 526 $ 508 $ 1,030 $ 998 Time-based and restricted stock 724 475 1,437 744 ESPP 17 15 34 211 Total stock based compensation $ 1,267 $ 998 $ 2,501 $ 1,953 In the fourth quarter of 2016 we determined that only 50% of the 2015 and 2016 performance grants made under the 2015 LTIP are expected to vest based on the related performance criteria and our assessment of the anticipated future performance applied to the performance criteria. As such, expenses listed in the table above reflect only the portion of grants and related expense that we anticipate will vest for those awards.

Income Taxes

Income Taxes	6 Months Ended
Income Taxes	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Spok files a consolidated U.S. Federal income tax return and income tax returns in various state, local and foreign jurisdictions as required. The Tax Cuts and Jobs Act of 2017 ("2017 Tax Act") was signed into law on December 22, 2017. As we complete our analysis of the 2017 Tax Act, collect and prepare necessary data, and interpret any additional guidance issued by the U.S. Treasury Department, the IRS, and other standard-setting bodies, we may make adjustments to the provisional amounts that were included in our 2017 Annual Report. Provisional amounts particularly include calculation of earnings and profits in foreign jurisdictions. Those adjustments may materially impact our provision for income taxes in the period in which the adjustments are made. Our quarterly tax provision, and our quarterly estimate of our annual effective tax rate, is subject to significant variation due to several factors, including variability in accurately predicting our pre-tax and taxable income and loss and the mix of jurisdictions to which they relate, changes in how we do business, changes in our stock price, foreign currency gains (losses), tax law developments (including changes in statutes, regulations, case law, and administrative practices), and relative changes of expenses or losses for which tax benefits are not recognized. Additionally, our effective tax rate can be more or less volatile based on the amount of pre-tax income or loss. For example, the impact of discrete items and non-deductible expenses on our effective tax rate is greater when our pre-tax income is lower. For 2018, the anticipated effective income tax rate is expected to continue to differ from the Federal statutory rate of 21% primarily due to the effect of state income taxes, research and development credits, permanent differences between book and taxable income and certain discrete items. At June 30, 2018 , we had total deferred income tax assets ("DTAs") of $46.3 million and no valuation allowance. This reflects a decrease of $1.4 million from the December 31, 2017 balance of DTAs of $47.7 million and no valuation allowance. The change from December 31, 2017 to June 30, 2018 primarily reflects the tax impact related to the acceleration of revenues and adjustment to beginning retained earnings resulting from the adoption of ASC 606 partially offset by assets created from estimated net operating losses incurred during the six months months ended June 30, 2018. We consider both positive and negative evidence when evaluating the recoverability of our DTAs. The assessment is required to determine whether based on all available evidence, it is more likely than not (i.e., greater than a 50% probability) that all or some portion of the DTAs will be realized in the future. During the fourth quarter of each year, we update our multi-year forecast of taxable income for our operations which assists in analyzing the recoverability of our DTAs.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
Commitments and Contingencies	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES There have been no material changes during the six months ended June 30, 2018 to the commitments and contingencies previously reported in the 2017 Annual Report and and our Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2018.

Related Parties

Related Parties	6 Months Ended
Related Parties	Jun. 30, 2018
Related Party Transactions [Abstract]
Related Parties	RELATED PARTIES A member of our Board of Directors also serves as a director for an entity that leases transmission tower sites to the Company. For the three months ended June 30, 2018 and 2017 , we incurred site rent expenses of $0.9 million and $1.0 million , respectively, and for the six months ended June 30, 2018 and 2017, we incurred site rent expenses of $1.8 million and $2.0 million , respectively, from the entity on which the individual serves as a director. Site rent expenses are included in Service, Rental and Maintenance expenses on the Condensed Consolidated Statement of Operations.

Organization and Significant 18

Organization and Significant Accounting Policies (Policies)	6 Months Ended
Organization and Significant Accounting Policies (Policies)	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying Condensed Consolidated Financial Statements include our accounts and the accounts of our wholly-owned direct and indirect subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. Our Condensed Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) and the rules and regulations of the United States Securities and Exchange Commission (the “SEC”). In management's opinion, the unaudited Condensed Consolidated Financial Statements include all adjustments and accruals that are necessary for a fair presentation of the results of all interim periods reported herein and all such adjustments are of a normal, recurring nature. As a result of the adoption of Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers , and our application of the modified retrospective approach, prior period amounts have not been restated under ASC 606. Amounts shown on the Condensed Consolidated Statement of Operations within the operating expense categories of Cost of revenue; Research and development; Service, rental and maintenance; Selling and marketing; and General and administrative are recorded exclusive of depreciation, amortization and accretion. The financial information included herein, other than the Condensed Consolidated Balance Sheet as of December 31, 2017 , is unaudited. The Condensed Consolidated Balance Sheet at December 31, 2017 has been derived from, but does not include all, the disclosures contained in the audited Consolidated Financial Statements as of and for the year ended December 31, 2017 . These Condensed Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and accompanying notes included in the Company's Annual Report on Form 10-K for the year ended December 31, 2017 (the “ 2017 Annual Report”). The Condensed Consolidated Statement of Operations for the interim periods presented are not necessarily indicative of the results that may be expected for a full year.
Use of Estimates	Use of Estimates The preparation of these Condensed Consolidated Financial Statements requires management to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues, expenses and related disclosures. On an on-going basis, we evaluate estimates and assumptions, including, but not limited to, those related to the impairment of long-lived assets; intangible assets subject to amortization and goodwill; accounts receivable allowances; revenue recognition; determining standalone selling price ("SSP") of performance obligations; variable consideration; depreciation expense; asset retirement obligations; severance and income taxes. We base our estimates on historical experience and various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.
Revenue Recognition - Adoption of ASC 606 Revenue from Contracts with Customers	Revenue Recognition - Adoption of ASC 606 “Revenue from Contracts with Customers” The majority of our revenues are derived from short-term contracts related to the sale of wireless paging services and software solutions. Our arrangements exist primarily with customers in the healthcare market and to a lesser extent State and Federal governments, as well as large enterprise businesses. Under the typical payment terms of our software contracts customers will normally pay a material amount of the contract price immediately upon execution of the contract. The remaining payments are required when product is delivered, when services begin and, to a lesser extent, when services are completed. Wireless services are generally billed as incurred on a monthly basis. Our contracts will generally result in billings in excess of revenue recognized, which we present as deferred revenues on the Condensed Consolidated Balance Sheets, primarily due to the receipt of payment in advance of product or services being provided. Amounts billed and due from our customers are classified as receivables on the Condensed Consolidated Balance Sheets. At times, we may have contracts which require us to perform work or provide products prior to billing which will generally result in revenue recognized in excess of billings. This excess is presented as unbilled receivables in the Notes to the Condensed Consolidated Balance Sheets. We generally do not have transactions that include a significant financing component (whether payments are made in advance or in arrears) as our contracts typically take less than 12 months to complete once started. We would not adjust the total consideration for the effects of a significant financing component if we anticipate, at contract inception, that the period between when we transfer a promised good or service to a customer and when the customer pays for that good or service will be one year or less. We account for a contract when: (1) both parties have approved the contract through mutually signed agreements but at times may be done through other methods such as purchase orders or master agreements; (2) the rights of the parties have been identified; (3) payment terms have been identified; (4) the contract has commercial substance; and (5) collectability of consideration is probable. We also evaluate whether two or more contracts should be combined and accounted for as a single contract. In our evaluation, we consider criteria such as, but not limited to, whether: (1) the contracts are negotiated as a package with a single commercial objective; (2) the amount of consideration to be paid in one contract is dependent on the price or performance of another contract; and (3) some or all of the goods or services promised in the contracts are a single performance obligation. Should we consider contracts related, we would account for those contracts as if they were a single contract. Evaluating whether two or more contracts should be combined and accounted for as a single contract requires significant judgment. In the aggregate, a decision to combine a group of contracts could significantly impact the amount of revenue and profit recorded in a given period. We review each contract to determine whether to account for the various promises as one or more performance obligations. The assessment and determination of performance obligations for a given contract requires significant judgment. Contracts which include wireless services are generally considered to be a single promise and therefore accounted for as a single performance obligation. Less commonly, however, we may promise to provide other distinct goods or services in conjunction with wireless services in which case we would account for the contract as having multiple performance obligations. Contracts which include goods or services related to our software solutions are generally sold with multiple promises and therefore will often include multiple performance obligations. Material performance obligations related to the sale of our software solutions include software licenses, professional services, hardware and maintenance, of which professional services and maintenance are generally considered a series of performance obligations. More often than not, total consideration will equate to the stated value on the contract taking into consideration any period or term over which services are to be provided, if applicable. However, we could have contracts in which variable consideration is present. It is common for our contracts which include wireless services to contain customer penalties if rental pagers are not returned and fees for usage of services in excess of the contractually allotted amount for a given period. It is also common for our contracts that include professional services to include travel related costs. These are costs which we incur in the normal course of delivering professional services and are generally billable to the customer based on our incurred expenses. These elements of variable consideration are fully constrained when an agreement is initially executed and are generally not considered estimable until the penalties, fees or costs have been incurred or are otherwise known. We include estimated amounts in the transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved. Estimating variable consideration requires significant judgment and our assessment includes all relevant information that is reasonably available to us including historical, current and forecasted information. We have elected to exclude from revenue, all amounts collected on behalf of third parties, and therefore, items such as sales and use tax are excluded from our calculation of the total transaction price. If a contract is separated into more than one performance obligation we allocate the total transaction price to each performance obligation proportionately based on the estimated relative SSPs of the promised goods or services underlying each performance obligation. We rarely sell goods or services with readily observable standalone sales, however, if we do, the observable standalone sales are used to determine the SSP. In most cases, we must estimate the relative SSP which requires significant judgment and estimates. In instances where SSP is not directly observable we determine the SSP using information that may include contractually stated prices, market conditions, costs, renewal contracts, list prices and other observable inputs. A discount is present if the total transaction price is less than the sum of the estimated SSPs of the goods or services promised in the contract. Discounts are generally allocated proportionately based on the relative SSP of the identified performance obligations for a given contract. Our wireless, professional and maintenance services are generally recognized over time due to a customer's simultaneous receipt and consumption of the benefit as we perform the work. As we transfer control over time, we recognize revenue based on the extent of progress towards completion of the performance obligation. The selection of the method to measure progress towards completion requires significant judgment and is based on the nature of the products or services to be provided. Generally, we use the time-elapsed measure of progress for performance obligations which include wireless or maintenance services. We believe this method best depicts the simultaneous transfer and consumption of the benefit based on our performance as these services are generally considered standby services. For professional services, we leverage an input methodology based on the number of hours worked on a project versus the total expected hours necessary to complete the project. Revenues are recognized proportionally as hours are incurred. This is a significant area of judgment as it requires an estimate to complete (“ETC”) for each contract. Our initial ETC is primarily based on prior experience also taking into consideration any specific facts and circumstances for a given contract. As projects progress, the ETC is periodically updated and reviewed to ensure the timing of revenue recognition is appropriate. The creation, maintenance and review of a projects ETC requires significant judgment to determine an appropriate number of hours over which the remaining project is expected to be completed. Our software licenses and hardware are generally recognized at a point in time when we have transferred control to the customer. For software licenses, revenue is not recognized until the related license(s) has been made available to the customer and the customer can begin to benefit from its right to use the license(s). Our software licenses represent a right to use Spok’s Intellectual Property (“IP”) as it exists at a point in time at which the license is granted. Many of our software licenses have significant standalone functionality due to their ability to process a transaction or perform a function or task, and we do not need to maintain those products, once provided to the customer, for value to exist. While the functionality of IP that we license may substantively change during the license period, customers are not contractually or practically required to update their license as a result of those changes. Assessing when transfer of control has occurred requires significant judgment. In most contracts transfer of control for software licenses occurs in a short period of time after a contract has been executed and licenses are made electronically available. Contracts may be modified to account for changes in a project's scope or other customer requirements. Most of our contract modifications are for goods or services that are distinct from the existing contract or may or may not be distinct but are for services which relate to a series of performance obligations. In these instances, the contract modification would either be recognized as an entirely new and separate contract or the modification would be treated as if it were a termination of the existing contract and the creation of a new contract including all untransferred goods and services under the previous contract. Revenue would be recognized on a prospective basis and a cumulative catch-up would not be recognized. Incremental costs of obtaining a contract and costs to fulfill a contract Commissions Expense - Our incremental costs primarily relate to sales commissions. We capitalize commissions and proportionally recognize the related expense to revenue as it is recognized on the underlying performance obligations. Some of these costs may relate to specific future anticipated contracts, specifically future maintenance renewals, which we do not pay commensurate sales commissions on. We amortize commission costs proportionally with revenue, thus it is necessary for us to estimate future revenues when there are future anticipated contracts. We estimate future revenues based on anticipated renewal amounts over an expected useful life (e.g. the period over which we believe the initial sales commissions relate to future anticipated contracts). The expected useful life is based on a review of our product life cycles, customer upgrade patterns and the rate at which customers renew maintenance. Commissions expenses are classified as Selling and Marketing on the Condensed Consolidated Statement of Operations.

Significant Accounting Polici19

Significant Accounting Policies Update (Tables)	6 Months Ended
Significant Accounting Policies Update (Tables)	Jun. 30, 2018
Accounting Policies [Abstract]
Schedule of Revenue Recognition	The following table presents Financial Statement components impacted as a result of adopting ASC 606, stated under ASC 605 for comparative purposes: For the Three Months Ended June 30, For the Six Months Ended June 30, 2018 2017 2018 2017 (Dollars in thousands) ASC 606 ASC 605 ASC 605 ASC 606 ASC 605 ASC 605 Condensed Consolidated Statement of Operations Revenues: Software $ 16,970 $ 18,136 $ 16,686 $ 35,815 $ 36,324 $ 32,270 Operating expenses: Selling and marketing $ 6,093 $ 6,198 $ 5,329 $ 12,562 $ 12,228 $ 11,251 Condensed Consolidated Statement of Comprehensive Income Other comprehensive (loss) income, net of tax: $ (342 ) $ (308 ) $ 82 $ (598 ) $ (472 ) $ 86 June 30, 2018 December 31, 2017 (Dollars in thousands) ASC 606 ASC 605 ASC 605 Condensed Consolidated Balance Sheets Current assets: Accounts receivable, net $ 35,574 $ 33,010 $ 32,279 Current assets: Prepaid expenses and other $ 7,050 $ 6,710 $ 5,752 Current liabilities: Deferred revenue $ 32,449 $ 34,667 $ 31,414 Non-current liabilities: Deferred revenue $ 961 $ 1,176 $ 1,063 Stockholder equity: Accumulated other comprehensive loss $ (1,850 ) $ (1,604 ) $ (1,088 ) Stockholder equity: Retained earnings $ 191,012 $ 185,429 $ 191,796

Revenue, Deferred Revenue And20

Revenue, Deferred Revenue And Deferred Commissions (Tables)	6 Months Ended
Revenue, Deferred Revenue And Deferred Commissions (Tables)	Jun. 30, 2018
Revenue from Contract with Customer [Abstract]
Schedule of Revenue	The following table presents our revenues disaggregated by revenue type: For the Three months ended June 30, For the Six Months Ended June 30, (Dollars in thousands) 2018 2017 (1) 2018 2017 (1) Wireless products and services $ 23,658 $ 25,639 $ 47,927 $ 51,499 Subscription 441 623 861 1,167 Software licenses 1,552 1,641 5,508 2,812 Professional services 4,363 3,650 8,433 7,003 Hardware 1,107 1,127 2,132 2,100 Maintenance 9,507 9,645 18,881 19,188 Total revenue $ 40,628 $ 42,325 $ 83,742 $ 83,769 (1) Prior period amounts have not been adjusted under the modified retrospective method for the adoption of ASC 606. Revenue by geographic region consisted of the following for the periods stated: For the Three months ended June 30, For the Six Months Ended June 30, (Dollars in thousands) 2018 2017 (1) 2018 2017 (1) Revenue United States $ 39,109 $ 40,869 $ 81,044 $ 81,374 International 1,519 1,456 2,698 2,395 Total revenue $ 40,628 $ 42,325 $ 83,742 $ 83,769 (1) Prior period amounts have not been adjusted under the modified retrospective method for the adoption of ASC 606.
Schedule of Deferred Revenue	Changes in the balance of total deferred revenue during the six months ended June 30, 2018 are as follows: (Dollars in thousands) December 31, 2017 Additions Revenue Recognized(1) June 30, 2018 Deferred Revenue $ 32,477 $ 30,976 $ (30,043 ) $ 33,410
Schedule of Deferred Commissions	Changes in the balance of total deferred commissions during the six months ended June 30, 2018 are as follows: (Dollars in thousands) December 31, 2017 Additions (1) Commissions Recognized June 30, 2018 Deferred Commissions $ 1,676 $ 3,647 $ (3,168 ) $ 2,155 (1) Includes $0.7 million in previously recognized commissions expense which was removed from retained earnings and included in deferred commissions resulting from the adoption of ASC 606.

Consolidated Financial Statem21

Consolidated Financial Statement Components (Tables)	6 Months Ended
Consolidated Financial Statement Components (Tables)	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Depreciation, Amortization and Accretion	Depreciation, amortization and accretion expenses consisted of the following for the periods stated: For the Three Months Ended June 30, For the Six Months Ended June 30, (Dollars in thousands) 2018 2017 2018 2017 Depreciation Leasehold improvements $ 67 $ 75 $ 135 $ 125 Asset retirement costs (76 ) (97 ) (152 ) (195 ) Paging and computer equipment 1,815 2,028 3,670 4,087 Furniture, fixtures and vehicles 103 76 209 141 Total depreciation 1,909 2,082 3,862 4,158 Amortization 625 629 1,250 1,636 Accretion 135 140 270 280 Total depreciation, amortization and accretion expense $ 2,669 $ 2,851 $ 5,382 $ 6,074
Property, Plant and Equipment	Property and equipment, net consisted of the following as of the date stated: (Dollars in thousands) Useful Life June 30, 2018 December 31, 2017 Leasehold improvements shorter of useful life or lease term $ 4,135 $ 4,107 Asset retirement costs 1-5 3,267 3,228 Paging and computer equipment 1-5 101,526 103,520 Furniture, fixtures and vehicles 3-5 5,345 4,545 Total property and equipment 114,273 115,400 Accumulated depreciation (101,238 ) (102,001 ) Total property and equipment, net $ 13,035 $ 13,399
Components of Other Current Liabilities	Other current liabilities consisted of the following as of the date stated: (Dollars in thousands) June 30, 2018 December 31, 2017 Accrued network costs, asset retirement obligations and other $ 2,496 $ 2,173 Accrued outside services 1,514 2,437 Total other current liabilities $ 4,010 $ 4,610
Summary of Other Non-Current Liabilities	Other non-current liabilities consisted of the following as of the date stated: (Dollars in thousands) June 30, 2018 December 31, 2017 Asset retirement obligations $ 7,351 $ 7,174 Other 1,042 901 Total other non-current liabilities $ 8,393 $ 8,075

Intangible Assets, Net (Tables)

Intangible Assets, Net (Tables)	6 Months Ended
Intangible Assets, Net (Tables)	Jun. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Net Consolidated Balance of Amortizable Intangible Assets	The net consolidated balance of intangible assets consisted of the following at June 30, 2018 : June 30, 2018 (Dollars in thousands) Useful Life Gross Carrying Accumulated Net Balance Customer relationships 10 $ 25,002 $ (18,335 ) $ 6,667 Total amortizable intangible assets $ 25,002 $ (18,335 ) $ 6,667
Estimated Amortization of Intangible Assets	Estimated amortization of intangible assets for future periods was as follows: (Dollars in thousands) For the remaining six months ending December 31, 2018 $ 1,250 For the year ending December 31: 2019 2,500 2020 2,500 2021 417 Total amortizable intangible assets $ 6,667

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	6 Months Ended
Asset Retirement Obligations (Tables)	Jun. 30, 2018
Asset Retirement Obligation Disclosure [Abstract]
Changes in Asset Retirement Obligation Liabilities	The components of the changes in the asset retirement obligation liabilities were: (Dollars in thousands) Short-Term Long-Term Total Balance at January 1, 2018 $ 235 $ 7,174 $ 7,409 Accretion (45 ) 315 270 Amounts paid (83 ) — (83 ) Increases — 39 39 Reclassifications 177 (177 ) — Balance at June 30, 2018 $ 284 $ 7,351 $ 7,635

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
Stockholders' Equity (Tables)	Jun. 30, 2018
Equity [Abstract]
Changes in Stockholders' Equity	Changes in stockholders’ equity for the six months ended June 30, 2018 consisted of the following: (Dollars in thousands) Balance at January 1, 2018 $ 290,529 Adjustment to beginning balance resulting from adoption of ASC 606 6,258 Net loss for the six months, ended June 30, 2018 (465 ) Estimated tax impact resulting from adoption of ASC 606 (1,614 ) Cash dividends declared (5,127 ) Common stock repurchase program (9,467 ) Amortization of stock based compensation 2,501 Repurchase of common stock for tax withholdings (894 ) Cumulative translation adjustment (598 ) Issuance of common stock under the Employee Stock Purchase Plan 143 Balance at June 30, 2018 $ 281,266
Cash Dividends Declared	The following table details our cash dividends declared in 2018 . Cash dividends paid as disclosed in the Condensed Consolidated Statement of Cash Flows for the six months ended June 30, 2018 and 2017 include previously declared cash dividends on shares of vested restricted common stock ("restricted stock") issued to our non-executive directors and dividends related to vested restricted stock units ("RSUs") issued to eligible employees. Cash dividends on RSUs and restricted stock have been accrued and are paid when the applicable vesting conditions are met. Accrued cash dividends on forfeited restricted stock and RSUs are also forfeited. Declaration Date Record Date Payment Date Per Share Amount Total Declared (1) (Dollars in thousands) February 28, 2018 March 16, 2018 March 30, 2018 $ 0.125 $ 2,589 April 25, 2018 May 25, 2018 June 22, 2018 0.125 2,538 Total $ 0.250 $ 5,127 (1) The total declared reflects the cash dividends declared in relation to common stock and unvested RSUs.
Share Repurchase Plan	The following table presents information with respect to purchases made by the Company during the six months ended June 30, 2018 : Period Total Number of Shares Purchased Average Price Paid Per Share (1) Total Number of Shares Purchased as Part of Publicly Announced Plans or Programs Approximate Dollar Value of Shares That May Yet Be Purchased Under the Plans or Programs (Dollars in thousands) Three Months Ended March 31, 2018 127,792 $ 15.04 127,792 $ 8,077 Three Months Ended June 30, 2018 501,782 14.99 501,782 $ 558 Total 629,574 $ 15.00 629,574 (1) Average price paid per share excludes commissions of approximately $25,183 .
Basic and Diluted Net Income Per Common Shares	The components of basic and diluted net (loss) income per common share were as follows for the periods stated: For the Three Months Ended June 30, For the Six Months Ended June 30, (in thousands, except for share and per share amounts) 2018 2017 2018 2017 Numerator: Net (loss) income $ (976 ) $ 1,498 $ (465 ) $ 2,352 Denominator: Basic weighted average outstanding shares of common stock 19,750,941 20,353,801 19,888,606 20,441,781 Diluted weighted average outstanding shares of common stock 19,750,941 20,366,102 19,888,606 20,508,473 Basic net (loss) income per common share $ (0.05 ) $ 0.07 $ (0.02 ) $ 0.12 Diluted net (loss) income per common share $ (0.05 ) $ 0.07 $ (0.02 ) $ 0.11
Antidilutive Securities Excluded from Computation of Net Income Per Share	For the three and six months ended June 30, 2018 and 2017 the following securities were excluded from the calculation of diluted shares outstanding as the effect would have been anti-dilutive: For the Three Months Ended June 30, For the Six Months Ended June 30, 2018 2017 2018 2017 Restricted stock units $ 77,190 $ — $ 145,526 $ —
Activities Under Equity Plan	The following table summarizes the activities under the ESPP from January 1, 2018 through June 30, 2018 : Activity Total ESPP equity securities available at January 1, 2018 228,279 ESPP common stock purchased by eligible employees (11,581 ) Total ESPP securities available at June 30, 2018 216,698 The following table summarizes the activities under the 2012 Equity Incentive Award Plan ("2012 Equity Plan") from January 1, 2018 through June 30, 2018 : Activity Total equity securities available at January 1, 2018 1,140,658 RSU and restricted stock awarded to eligible employees, net of forfeitures (337,640 ) Total equity securities available at June 30, 2018 803,018
Summary of Outstanding RSUs under 2011 LTIP	The following table details activities with respect to outstanding RSUs and restricted stock for the six months ended June 30, 2018 : Shares Weighted- Unvested at January 1, 2018 (1) 393,084 $ 18.54 Granted 334,035 16.47 Vested — — Forfeited (8,489 ) 17.72 Unvested at June 30, 2018 (1) 718,630 $ 17.59 (1) Approximately 99,451 RSUs from the 2016 grant are not expected to vest based on the Company's current assessment of the related performance obligations.
Stock Based Compensation Expense	The following table reflects the items for stock based compensation expense on the Condensed Consolidated Statement of Operations for the periods stated: For the Three Months Ended June 30, For the Six Months Ended June 30, (Dollars in thousands) 2018 2017 2018 2017 Performance-based RSUs $ 526 $ 508 $ 1,030 $ 998 Time-based and restricted stock 724 475 1,437 744 ESPP 17 15 34 211 Total stock based compensation $ 1,267 $ 998 $ 2,501 $ 1,953

Organization and Significant 25

Organization and Significant Accounting Policies (Detail) $ in Thousands, message in Millions	6 Months Ended
	Jun. 30, 2018USD ($)message	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Monthly messages sent through company solutions (more than) \| message	100
Reclassification to accumulated other comprehensive income	$ (1,850)		$ (1,088)
Accounting Standards Update 2014-09 \| ASC 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Reclassification from additional paid in capital		$ 1,500	1,100
Reclassification to accumulated other comprehensive income		$ 1,500	$ 1,100

Recent and Pending Accounting26

Recent and Pending Accounting Standards (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	$ 191,012		$ 191,796
Decrease to deferred revenue	(33,410)		(32,477)
Decrease to accumulated other comprehensive income	1,850		1,088
ASC 606 \| Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings			6,400
Decrease to deferred revenue	$ 4,200		4,200
Decrease to accumulated other comprehensive income		$ (1,500)	(1,100)
Unbilled receivables			1,300
Prepaid commissions			700
ASC 606 \| Accounting Standards Update 2014-09, Translation Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease to accumulated other comprehensive income			$ 200

Significant Accounting Polici27

Significant Accounting Policies Update (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues: Software	$ 40,628	$ 42,325	$ 83,742	$ 83,769
Operating expenses: Selling and marketing	6,093	5,329	12,562	11,251
Other comprehensive (loss) income, net of tax: foreign currency translation adjustments	(342)	82	(598)	86
Current assets: Accounts receivable, net	35,574		35,574
Current assets: Prepaid expenses and other	7,050		7,050		$ 5,752
Current liabilities: Deferred revenue	32,449		32,449		31,414
Non-current liabilities: Deferred revenue	961		961		1,063
Stockholder equity: Accumulated other comprehensive loss	(1,850)		(1,850)		(1,088)
Stockholder equity: Retained earnings	191,012		191,012		191,796
ASC 605 \| Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating expenses: Selling and marketing	6,198	5,329	12,228	11,251
Other comprehensive (loss) income, net of tax: foreign currency translation adjustments	(308)	82	(472)	86
Current assets: Accounts receivable, net	33,010		33,010		32,279
Current assets: Prepaid expenses and other	6,710		6,710		5,752
Current liabilities: Deferred revenue	34,667		34,667		31,414
Non-current liabilities: Deferred revenue	1,176		1,176		1,063
Stockholder equity: Accumulated other comprehensive loss	(1,604)		(1,604)		(1,088)
Stockholder equity: Retained earnings	185,429		185,429		$ 191,796
Software
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues: Software	16,970	16,686	35,815	32,270
Software \| ASC 605 \| Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues: Software	$ 18,136	$ 16,686	$ 36,324	$ 32,270

Revenue, Deferred Revenue And28

Revenue, Deferred Revenue And Deferred Commissions (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)revenue_component	Jun. 30, 2017USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 40,628	$ 42,325	$ 83,742	$ 83,769
Deferred revenue recognized from previous period			16,500
Wireless products and services
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	23,658	25,639	47,927	51,499
Subscription
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	441	623	861	1,167
Software licenses
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	1,552	1,641	5,508	2,812
Professional services
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	4,363	3,650	8,433	7,003
Hardware
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 1,107	1,127	$ 2,132	2,100
Maintenance
Revenues from External Customers and Long-Lived Assets [Line Items]
Typical duration of revenue recognition	1 year		1 year
Total revenue	$ 9,507	9,645	$ 18,881	19,188
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	39,109	40,869	81,044	81,374
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 1,519	$ 1,456	$ 2,698	$ 2,395
Wireless
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue primary component \| revenue_component			2
Software
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue primary component \| revenue_component			2

Revenue, Deferred Revenue And29

Revenue, Deferred Revenue And Deferred Commissions - Deferred Revenues (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Contract With Customer, Asset And Liability [Roll Forward]
December 31, 2017	$ 32,477
Additions	5,191	$ 2,561
June 30, 2018	33,410
Accounting Standards Update 2014-09
Contract With Customer, Asset And Liability [Roll Forward]
Additions	30,976
Revenue recognized	(30,043)
ASC 606 \| Accounting Standards Update 2014-09
Contract With Customer, Asset And Liability [Roll Forward]
December 31, 2017	(4,200)
June 30, 2018	$ (4,200)

Revenue, Deferred Revenue And30

Revenue, Deferred Revenue And Deferred Commissions - Deferred Commissions (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018USD ($)
Sales Commissions
Capitalized Contract Cost [Line Items]
December 31, 2017	$ 1,676
Additions	3,647
Commissions Recognized	(3,168)
June 30, 2018	2,155
ASC 606 \| Accounting Standards Update 2014-09
Capitalized Contract Cost [Line Items]
June 30, 2018	$ 700

Consolidated Financial Statem31

Consolidated Financial Statement Components - Depreciation, Amortization and Accretion (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Property, Plant and Equipment [Line Items]
Depreciation	$ 1,909	$ 2,082	$ 3,862	$ 4,158
Amortization	625	629	1,250	1,636
Accretion	135	140	270	280
Total depreciation, amortization and accretion expense	2,669	2,851	5,382	6,074
Leasehold improvements
Property, Plant and Equipment [Line Items]
Depreciation	67	75	135	125
Asset retirement costs
Property, Plant and Equipment [Line Items]
Depreciation	(76)	(97)	(152)	(195)
Paging and computer equipment
Property, Plant and Equipment [Line Items]
Depreciation	1,815	2,028	3,670	4,087
Furniture, fixtures and vehicles
Property, Plant and Equipment [Line Items]
Depreciation	$ 103	$ 76	$ 209	$ 141

Consolidated Financial Statem32

Consolidated Financial Statement Components - Accounts Receivable, Net (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable	$ 1.5	$ 1.1
Contract Asset [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable	$ 10.1	$ 7.3

Consolidated Financial Statem33

Consolidated Financial Statement Components - Property and Equipment, Net (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 114,273	$ 115,400
Accumulated depreciation	(101,238)	(102,001)
Total property and equipment, net	13,035	13,399
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	4,135	4,107
Asset retirement costs
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 3,267	3,228
Asset retirement costs \| Minimum
Property, Plant and Equipment [Line Items]
Useful Life	1 year
Asset retirement costs \| Maximum
Property, Plant and Equipment [Line Items]
Useful Life	5 years
Paging and computer equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 101,526	103,520
Paging and computer equipment \| Minimum
Property, Plant and Equipment [Line Items]
Useful Life	1 year
Paging and computer equipment \| Maximum
Property, Plant and Equipment [Line Items]
Useful Life	5 years
Furniture, fixtures and vehicles
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 5,345	$ 4,545
Furniture, fixtures and vehicles \| Minimum
Property, Plant and Equipment [Line Items]
Useful Life	3 years
Furniture, fixtures and vehicles \| Maximum
Property, Plant and Equipment [Line Items]
Useful Life	5 years

Consolidated Financial Statem34

Consolidated Financial Statement Components - Other Current Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued network costs, asset retirement obligations and other	$ 2,496	$ 2,173
Accrued outside services	1,514	2,437
Total other current liabilities	$ 4,010	$ 4,610

Consolidated Financial Statem35

Consolidated Financial Statement Components - Other Non-current Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Asset retirement obligations	$ 7,351	$ 7,174
Other	1,042	901
Total other long-term liabilities	$ 8,393	$ 8,075

Intangible Assets, Net - Additi

Intangible Assets, Net - Additional Information (Detail)	6 Months Ended
Intangible Assets, Net - Additional Information (Detail)	Jun. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Useful Life (In Years)	10 years

Intangible Assets, Net - Net Co

Intangible Assets, Net - Net Consolidated Balance of Amortizable Intangible Assets (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	10 years
Gross Carrying Amount	$ 25,002
Accumulated Amortization	(18,335)
Total amortizable intangible assets	$ 6,667	$ 7,917
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	10 years
Gross Carrying Amount	$ 25,002
Accumulated Amortization	(18,335)
Total amortizable intangible assets	$ 6,667

Intangible Assets, Net - Estima

Intangible Assets, Net - Estimated Amortization of Intangible Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
For the remaining six months ending December 31, 2018	$ 1,250
2,019	2,500
2,020	2,500
2,021	417
Total amortizable intangible assets	$ 6,667	$ 7,917

Asset Retirement Obligations -

Asset Retirement Obligations - Changes in Asset Retirement Obligation Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at January 1, 2018			$ 7,409
Accretion	$ 135	$ 140	270	$ 280
Amounts paid			(83)
Increases			39
Reclassifications			0
Balance at June 30, 2018	7,635		7,635
Short-Term Portion
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at January 1, 2018			235
Accretion			(45)
Amounts paid			(83)
Increases			0
Reclassifications			177
Balance at June 30, 2018	284		284
Long-Term Portion
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at January 1, 2018			7,174
Accretion			315
Amounts paid			0
Increases			39
Reclassifications			(177)
Balance at June 30, 2018	$ 7,351		$ 7,351

Asset Retirement Obligations 40

Asset Retirement Obligations - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Asset Retirement Obligation Disclosure [Abstract]
Estimated liability	$ 9,000		$ 9,000
Accretion	$ 135	$ 140	$ 270	$ 280

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jul. 25, 2018	Feb. 28, 2018	Dec. 31, 2017	Dec. 31, 2016	May 16, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock authorized (shares)	75,000,000		75,000,000
Common stock par value (usd per share)	$ 0.0001		$ 0.0001
Preferred stock authorized (shares)	25,000,000		25,000,000
Preferred stock par value (usd per share)	$ 0.0001		$ 0.0001
Options outstanding (shares)	0		0				0
Common stock outstanding (shares)	19,472,249		19,472,249				20,135,514
Preferred stock outstanding (shares)	0		0				0
Stock repurchase authority						$ 10,000,000
Expected vesting percent								50.00%
Amount spent to repurchase common stock			$ 9,467,000
Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend rate (usd per share)					$ 0.125
Dividends declared					$ 2,400,000
2012 Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (shares)									2,194,986
2012 Equity Plan \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			1 year
2012 Equity Plan \| Restricted Stock and Restricted Stock Units with Contingent Performance Requirements
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			3 years
2012 Equity Plan \| Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			3 years
Performance-based RSUs \| Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments other than options, nonvested (shares)	718,630		718,630				393,084
Granted (shares)			334,035
2011 Long Term Incentive Plan \| Restricted Stock and Restricted Stock Units with Contingent Performance Requirements
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments other than options, nonvested (shares)	362,974		362,974
2011 Long Term Incentive Plan \| Restricted Stock and Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost not yet recognized, share-based awards other than options	$ 5,900,000		$ 5,900,000
Weighted-average period over which cost is expected to be recognized			1 year 10 months 10 days
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (shares)	250,000		250,000
Award required holding period			2 years
Stock purchased during period (shares)	11,581	8,983	11,581	8,393
Stock purchased during period, value	$ 100,000		$ 100,000
Maximum \| ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Offering period, maximum			6 months

Stockholders' Equity - Changes

Stockholders' Equity - Changes in Stockholders' Equity (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at January 1, 2018			$ 290,529
Adjustment to beginning balance resulting from adoption of ASC 606					$ 6,258
Net loss for the six months, ended June 30, 2018	$ (976)	$ 1,498	(465)	$ 2,352
Estimated tax impact resulting from adoption of ASC 606			(1,614)
Cash dividends declared			(5,127)
Common stock repurchase program			(9,467)
Amortization of stock based compensation			2,501
Repurchase of common stock for tax withholdings			(894)
Cumulative translation adjustment			(598)
Issuance of common stock under the Employee Stock Purchase Plan			143
Balance at June 30, 2018	$ 281,266		$ 281,266

Stockholders' Equity - Cash Div

Stockholders' Equity - Cash Dividends Declared to Stockholders (Detail) - Common Stock $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2018USD ($)$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Per Share Amount (usd per share) \| $ / shares	$ 0.25
Total Declared \| $	$ 5,127
Installment One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Declaration Date	Feb. 28, 2018
Record Date	Mar. 16, 2018
Payment Date	Mar. 30, 2018
Per Share Amount (usd per share) \| $ / shares	$ 0.125
Total Declared \| $	$ 2,589
Installment Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Declaration Date	Apr. 25, 2018
Record Date	May 25, 2018
Payment Date	Jun. 22, 2018
Per Share Amount (usd per share) \| $ / shares	$ 0.125
Total Declared \| $	$ 2,538

Stockholders' Equity - Treasury

Stockholders' Equity - Treasury Stock (Detail) - USD ($)	3 Months Ended		6 Months Ended
Stockholders' Equity - Treasury Stock (Detail) - USD ($)	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2018
Equity, Class of Treasury Stock [Line Items]
Shares purchased during period (shares)	501,782	127,792
Total number of shares purchased (shares)	629,574		629,574
Average price paid per share (usd per share)	$ 14.99	$ 15.04
Average price paid per share (usd per share)	$ 15		$ 15
Treasury stock acquired during period			$ 9,467,000
Commissions paid to acquire shares			$ 25,183
Common Stock Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Shares purchased during period (shares)	501,782	127,792
Total number of shares purchased (shares)	629,574		629,574
Treasury stock acquired during period	$ 558,000	$ 8,077,000

Stockholders' Equity - Basic an

Stockholders' Equity - Basic and Diluted Net Income Per Common Shares (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Numerator:
Net (loss) income	$ (976)	$ 1,498	$ (465)	$ 2,352
Denominator:
Basic weighted average outstanding shares of common stock (shares)	19,750,941	20,353,801	19,888,606	20,441,781
Diluted weighted average outstanding shares of common stock (in shares)	19,750,941	20,366,102	19,888,606	20,508,473
Basic net (loss) income per common share (usd per share)	$ (0.05)	$ 0.07	$ (0.02)	$ 0.12
Diluted net (loss) income per common share (usd per share)	$ (0.05)	$ 0.07	$ (0.02)	$ 0.11

Stockholders' Equity - Antidilu

Stockholders' Equity - Antidilutive Securities Excluded from Computation of Net Income Per Share (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities	$ 77,190	$ 0	$ 145,526	$ 0

Stockholders' Equity - Activiti

Stockholders' Equity - Activities Under Equity Plan (Detail) - shares	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2018
ESPP
Share-based Compensation Arrangement By Share-based Payment Award, Shares Authorized [Roll Forward]
Shares available for grant (shares)		228,279
ESPP common stock purchased by eligible employees (in shares)	0	(11,581)
Shares available for grant (shares)		216,698
Restricted stock units \| 2012 Equity Plan
Share-based Compensation Arrangement By Share-based Payment Award, Shares Authorized [Roll Forward]
Shares available for grant (shares)		1,140,658
Shares available for grant (shares)		803,018
Eligible Employees \| Restricted stock units \| 2012 Equity Plan
Share-based Compensation Arrangement By Share-based Payment Award, Shares Authorized [Roll Forward]
RSU and restricted stock awarded to eligible employees, net of forfeitures (shares)		(337,640)

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Outstanding RSUs (Detail)	6 Months Ended
Stockholders' Equity - Summary of Outstanding RSUs (Detail)	Jun. 30, 2018$ / sharesshares
Restricted stock units \| Performance-based RSUs
Shares
Beginning Balance (shares)	393,084
Granted (shares)	334,035
Vested (shares)	0
Forfeited (shares)	(8,489)
Ending Balance (shares)	718,630
Weighted- Average Grant Date Fair Value
Beginning Balance, Weighted Average Grant Date Fair Value (usd per share) \| $ / shares	$ 18.54
Granted, Weighted Average Grant Date Fair Value (usd per share) \| $ / shares	16.47
Vested, Weighted Average Grant Date Fair Value (usd per share) \| $ / shares	0
Forfeited, Weighted Average Grant Date Fair Value (usd per share) \| $ / shares	17.72
Ending Balance, Weighted Average Grant Date Fair Value (usd per share) \| $ / shares	$ 17.59
Restricted Stock and Restricted Stock Units (RSUs) \| 2011 Long Term Incentive Plan
Weighted- Average Grant Date Fair Value
Shares not expected to vest (shares)	99,451

Stockholders' Equity - Stock-b

Stockholders' Equity - Stock-based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share based Compensation Allocation of Recognized Period Cost [Line Items]
Total stock based compensation expense	$ 1,267	$ 998	$ 2,501	$ 1,953
Performance-based RSUs
Share based Compensation Allocation of Recognized Period Cost [Line Items]
Total stock based compensation expense	526	508	1,030	998
Time-based and restricted stock
Share based Compensation Allocation of Recognized Period Cost [Line Items]
Total stock based compensation expense	724	475	1,437	744
ESPP
Share based Compensation Allocation of Recognized Period Cost [Line Items]
Total stock based compensation expense	$ 17	$ 15	$ 34	$ 211

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	6 Months Ended
Income Taxes - Additional Information (Detail) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Deferred income tax assets	$ 46,344,000	$ 47,679,000
Valuation allowance	0	$ 0
Decrease in deferred tax assets	$ 1,400,000

Related Parties - Additional In

Related Parties - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Director
Related Party Transaction [Line Items]
Site rent expense	$ 0.9	$ 1	$ 1.8	$ 2