Significant Accounting Policies Update	9 Months Ended
Sep. 30, 2018
Accounting Policies [Abstract]
Significant Accounting Policies Update	Significant Accounting Policies Update The Company's significant accounting policies are detailed in Note 2 of its annual report on Form 10-K for the year ended December 31, 2017. As a result of the FASB's updated guidance for revenue recognition and related changes, as described in Note 1, the following policies have been updated as of the Company's adoption date of January 1, 2018, with retrospective application to the historical periods presented. Revenue Recognition The Company primarily derives revenue from the sale of services to customers executing contracts having terms of one year or longer. Services included in the Company's contracts consist of its core services – the delivery of content, applications and software over the Internet – as well as security solutions and professional services. Revenue is recognized upon transfer of control of promised services in an amount that reflects the consideration the Company expects to receive in exchange for those services. The Company enters into contracts that may include various combinations of these services, which are generally capable of being distinct and accounted for as separate performance obligations. These contracts generally commit the customer to a minimum of monthly, quarterly or annual levels of usage and specify the rate at which the customer must pay for actual usage above the stated minimum. Based on the typical structure of the Company's contracts, which are generally for monthly recurring services that are essentially the same over time and have the same pattern of transfer to the customer, most performance obligations represent a promise to deliver a series of distinct services over time. The Company's contracts with customers sometimes include promises to deliver multiple services to a customer. Determining whether services are distinct performance obligations often requires the exercise of judgment by management. For example, advanced features that enhance a service and are highly interrelated are generally not considered distinct; rather, they are combined with the service they relate to into one performance obligation. Different determinations related to combining services into performance obligations could result in differences in the timing and amount of revenue recognized in a period. Generally, the transaction price in a contract is equal to the committed price stated in the contract, less any discounts or rebates. The Company's typical contracts qualify for series accounting and the pricing terms generally do not require estimation of the transaction price beyond the reporting period. As a result, any incremental fees generated as a result of usage or “bursting” over committed contract levels are recorded in the period to which the services relate. The amount of consideration recognized for usage above contract minimums is limited to the amount the Company expects to be entitled to receive in exchange for providing the services. Once the transaction price has been determined, the Company allocates such price among all performance obligations in the contract on a relative standalone selling price (“SSP”) basis. Determination of SSP requires the exercise of judgment by management. SSP is based on observable inputs such as the price the Company charges for the service when sold separately, or the discounted list price per management’s approved price list. In cases where services are not sold separately or price list rates are not available, a cost-plus-margin approach or adjusted market approach is used to determine SSP. Most content delivery and security services represent stand-ready obligations that are satisfied over time as the customer simultaneously receives and consumes the benefits provided by the Company. Accordingly, revenue for those services is recognized over time, generally ratably over the term of the arrangement due to consistent monthly traffic commitments that expire each period. Any bursting over given commitments is recognized in the period in which the traffic was served. For services that involve traffic consumption, revenue is recognized in an amount that reflects the level of traffic served to a customer in a given period. For custom arrangements, other methods may be used as a measure of progress towards satisfying the performance obligations. Some of the Company's services are satisfied at a point in time, such as one-time professional services contracts, integration services and most license sales where the primary obligation is delivery of the license at the start of the term. In these cases, revenue is recognized at the point in time of delivery or satisfaction of the performance obligation. From time to time, the Company enters into contracts to sell its services or license its technology to unrelated enterprises at or about the same time that it enters into contracts to purchase products or services from the same enterprises. Consideration payable to a customer is reviewed as part of the transaction price. If the payment to the customer does not represent payment for a distinct service, revenue is recognized only up to the net amount of consideration after customer payment obligations are considered. The Company may also resell the licenses or services of third parties. If the Company is acting as an agent in an arrangement with a customer to provide third party services, the transaction price reflects only the net amount to which the Company will be entitled, after accounting for payments made to the third party responsible for satisfying the performance obligation. Incremental Costs to Obtain a Contract with a Customer The Company capitalizes incremental costs associated with obtaining customer contracts, specifically certain commission and incentive payments. The Company pays commissions and incentives up-front based on contract value upon signing a new arrangement with a customer and upon renewal and upgrades of existing contracts with customers if the renewal and upgrades result in an incremental increase in contract value. To the extent commissions and incentives are earned, the expenses, including estimated payroll taxes, are deferred on the Company's consolidated balance sheet and amortized over the expected life of the customer arrangement on a straight-line basis. The Company also incurs commission expense on an ongoing basis based upon revenue recognized. In these cases, no incremental costs are deferred, as the commissions are earned and expensed in the same period for which the associated revenue is recognized. Based on the nature of the Company's unique technology and services, and the rate at which the Company continually enhances and updates its technology, the expected life of the customer arrangement is determined to be approximately 2.5 years. Amortization is primarily included in sales and marketing expense in the consolidated statements of income. The current portion of deferred commission and incentive payments is included in prepaid expenses and other current assets, and the long-term portion is included in other assets on the Company's consolidated balance sheets. Contract Liabilities Contract liabilities primarily represent payments received from customers for which the related performance obligations have not yet been satisfied. These balances consist of the unearned portion of monthly service fees and integration fees, and prepayments made by customers for future periods. The current and long-term portions of the Company's contract liabilities are included in deferred revenue in the respective sections of the Company's consolidated balance sheets.

Significant Accounting Policies Update

The Company's significant accounting policies are detailed in Note 2 of its annual report on Form 10-K for the year ended December 31, 2017. As a result of the FASB's updated guidance for revenue recognition and related changes, as described in Note 1, the following policies have been updated as of the Company's adoption date of January 1, 2018, with retrospective application to the historical periods presented.

Revenue Recognition

The Company primarily derives revenue from the sale of services to customers executing contracts having terms of one year or longer. Services included in the Company's contracts consist of its core services – the delivery of content, applications and software over the Internet – as well as security solutions and professional services. Revenue is recognized upon transfer of control of promised services in an amount that reflects the consideration the Company expects to receive in exchange for those services.

The Company enters into contracts that may include various combinations of these services, which are generally capable of being distinct and accounted for as separate performance obligations. These contracts generally commit the customer to a minimum of monthly, quarterly or annual levels of usage and specify the rate at which the customer must pay for actual usage above the stated minimum. Based on the typical structure of the Company's contracts, which are generally for monthly recurring services that are essentially the same over time and have the same pattern of transfer to the customer, most performance obligations represent a promise to deliver a series of distinct services over time.

The Company's contracts with customers sometimes include promises to deliver multiple services to a customer. Determining whether services are distinct performance obligations often requires the exercise of judgment by management. For example, advanced features that enhance a service and are highly interrelated are generally not considered distinct; rather, they are combined with the service they relate to into one performance obligation. Different determinations related to combining services into performance obligations could result in differences in the timing and amount of revenue recognized in a period.

Generally, the transaction price in a contract is equal to the committed price stated in the contract, less any discounts or rebates. The Company's typical contracts qualify for series accounting and the pricing terms generally do not require estimation of the transaction price beyond the reporting period. As a result, any incremental fees generated as a result of usage or “bursting” over committed contract levels are recorded in the period to which the services relate. The amount of consideration recognized for usage above contract minimums is limited to the amount the Company expects to be entitled to receive in exchange for providing the services. Once the transaction price has been determined, the Company allocates such price among all performance obligations in the contract on a relative standalone selling price (“SSP”) basis.

Determination of SSP requires the exercise of judgment by management. SSP is based on observable inputs such as the price the Company charges for the service when sold separately, or the discounted list price per management’s approved price list. In cases where services are not sold separately or price list rates are not available, a cost-plus-margin approach or adjusted market approach is used to determine SSP.

Most content delivery and security services represent stand-ready obligations that are satisfied over time as the customer simultaneously receives and consumes the benefits provided by the Company. Accordingly, revenue for those services is recognized over time, generally ratably over the term of the arrangement due to consistent monthly traffic commitments that expire each period. Any bursting over given commitments is recognized in the period in which the traffic was served. For services that involve traffic consumption, revenue is recognized in an amount that reflects the level of traffic served to a customer in a given period. For custom arrangements, other methods may be used as a measure of progress towards satisfying the performance obligations.

Some of the Company's services are satisfied at a point in time, such as one-time professional services contracts, integration services and most license sales where the primary obligation is delivery of the license at the start of the term. In these cases, revenue is recognized at the point in time of delivery or satisfaction of the performance obligation.

From time to time, the Company enters into contracts to sell its services or license its technology to unrelated enterprises at or about the same time that it enters into contracts to purchase products or services from the same enterprises. Consideration payable to a customer is reviewed as part of the transaction price. If the payment to the customer does not represent payment for a distinct service, revenue is recognized only up to the net amount of consideration after customer payment obligations are considered. The Company may also resell the licenses or services of third parties. If the Company is acting as an agent in an arrangement with a customer to provide third party services, the transaction price reflects only the net amount to which the Company will be entitled, after accounting for payments made to the third party responsible for satisfying the performance obligation.

Incremental Costs to Obtain a Contract with a Customer

The Company capitalizes incremental costs associated with obtaining customer contracts, specifically certain commission and incentive payments. The Company pays commissions and incentives up-front based on contract value upon signing a new arrangement with a customer and upon renewal and upgrades of existing contracts with customers if the renewal and upgrades result in an incremental increase in contract value. To the extent commissions and incentives are earned, the expenses, including estimated payroll taxes, are deferred on the Company's consolidated balance sheet and amortized over the expected life of the customer arrangement on a straight-line basis. The Company also incurs commission expense on an ongoing basis based upon revenue recognized. In these cases, no incremental costs are deferred, as the commissions are earned and expensed in the same period for which the associated revenue is recognized.

Based on the nature of the Company's unique technology and services, and the rate at which the Company continually enhances and updates its technology, the expected life of the customer arrangement is determined to be approximately 2.5 years. Amortization is primarily included in sales and marketing expense in the consolidated statements of income. The current portion of deferred commission and incentive payments is included in prepaid expenses and other current assets, and the long-term portion is included in other assets on the Company's consolidated balance sheets.

Contract Liabilities

Contract liabilities primarily represent payments received from customers for which the related performance obligations have not yet been satisfied. These balances consist of the unearned portion of monthly service fees and integration fees, and prepayments made by customers for future periods. The current and long-term portions of the Company's contract liabilities are included in deferred revenue in the respective sections of the Company's consolidated balance sheets.