The following table presents our revenues by primary product and service offering (in thousands):

The following table presents our revenues disaggregated by geography (in thousands):

The timing of revenue recognition may differ from the timing of invoicing to customers. We generally have an unconditional right to consideration when we invoice our customers and record a receivable. We record a contract asset when revenue is recognized prior to invoicing, or a contract liability (deferred revenue) when revenue will be recognized subsequent to invoicing.

Contract assets generally result from our subscription programs where we satisfy a hardware performance obligation upon shipment to the customer, and the right to the portion of the transaction price allocated to that hardware performance obligation is conditional on our future performance of a SaaS service obligation under the contract. We recognize a portion of the amount allocated to hardware products shipped to the customer as accounts receivable when invoiced to the customer, and record the remaining allocated value as a contract asset as we have generally fulfilled our hardware performance obligation upon shipment. Unbilled accounts receivable expected to be invoiced and collected within twelve months was $13.9 million as of December 31, 2021, and was included in accounts and notes receivable, net on our consolidated balance sheet.

Contract liabilities generally consist of deferred revenue on our subscription programs where we generally invoice customers at the beginning of each annual contract period and record a receivable at the time of invoicing when there is an unconditional right to consideration.

Deferred revenue is comprised mainly of unearned revenue related to our Axon Evidence SaaS platform, secure cloud-based storage, service-type extended warranties, stand-ready obligations in our cartridge programs, and rights to future CED, camera and related accessories hardware in our subscription programs. Revenue for Axon Evidence and cloud-based storage, our service-type extended warranties and stand-ready cartridge programs is generally recognized on a straight-line basis over the subscription term. Revenue for the rights to future hardware is generally recognized at the point in time the hardware products are shipped to the customer.

Payment terms and conditions vary by contract type and geography, but our standard terms are that payments are due within 30 days from the date of invoice.

The following table presents our contract assets, contract liabilities and certain information related to these balances as of and for the year ended December 31, 2021 (in thousands):

Contract liabilities (deferred revenue) consisted of the following (in thousands):

As of December 31, 2021, we had approximately $2.80 billion of remaining performance obligations, which included both recognized contract liabilities as well as amounts that will be invoiced and recognized in future periods. The remaining performance obligations are limited only to arrangements that meet the definition of a contract under Topic 606 as of December 31, 2021. We expect to recognize between 15% - 20% of this balance over the next twelve months, and expect the remainder to be recognized over the following five to seven years, subject to risks related to delayed deployments, budget appropriation or other contract cancellation clauses.

We recognize an asset for the incremental costs of obtaining a contract with a customer, which consist primarily of sales commissions. These costs are ascribed to or allocated to the underlying performance obligations in the contract and amortized consistent with the recognition timing of the revenue for the underlying performance obligations.

For contract costs related to performance obligations with an amortization period of one year or less, we apply the practical expedient to expense these sales commissions when incurred. These costs are recognized as incurred within sales, general and administrative expenses on the accompanying consolidated statements of operations and comprehensive income.

As of December 31, 2021, our assets for costs to obtain contracts were as follows (in thousands):

(1)	Current deferred commissions are included within prepaid expenses and other current assets on the accompanying consolidated balance sheet.

(2)	Deferred commissions, net of current portion, are included in other assets on the accompanying consolidated balance sheet.

During the years ended December 31, 2021, 2020 and 2019, we recognized $16.6 million, $11.3 million, and $8.2 million, respectively, of amortization related to deferred commissions. These costs are recorded within sales, general and administrative expenses on the accompanying consolidated statements of operations and comprehensive income (loss).

Significant Judgments

Our contracts with certain municipal government customers may be subject to budget appropriation, other contract cancellation clauses or future periods which are optional. In contracts where the customer’s performance is subject to budget appropriation clauses, we generally consider the likelihood of non-appropriation to be remote when determining the contract term and transaction price. Contracts with other cancellation provisions or optional periods may require judgment in determining the contract term, including the existence of material rights, determining transaction price and identifying the performance obligations.

At times, customers may request changes that either amend, replace or cancel existing contracts. Judgment is required to determine whether the specific facts and circumstances within the contracts require the changes to be accounted for as a separate contract or as a modification. Generally, contract modifications containing additional goods and services that are determined to be distinct and sold at their SSP are accounted for as a separate contract. For contract modifications where both criteria are not met, the original contract is updated and the required adjustments to revenue and contract assets, liabilities, and other accounts are made accordingly.

Our contracts with customers often include promises to transfer multiple products and services to a customer. Determining whether products and services are considered distinct performance obligations that should be accounted for separately rather than together may require significant judgment. We consider CED devices and related accessories, as well as cameras and related accessories, to be separately identifiable from each other as well as from extended warranties on these products and the SaaS subscriptions to Axon Evidence and other cloud services.

In contracts where there are timing differences between when we transfer a promised good or service to the customer and when the customer pays for that good or service, we have determined that, with the exception of our TASER 60 installment purchase arrangements, our contracts generally do not include a significant financing component. For the years ended December 31, 2021, 2020, and 2019, we recorded interest income of $1.0 million, $1.5 million, and $1.6 million, respectively.

Judgment is required to determine the SSP for each distinct performance obligation. We analyze separate sales of our products and services as a basis for estimating the SSP of our products and services and then use that SSP as the basis for allocating the transaction price when our products and services are sold together in a contract with multiple performance obligations. In instances where the SSP is not directly observable, such as when we do not sell the product or service separately, we determine the SSP using information that may include market conditions, time value of money and other observable inputs. We typically have more than one SSP for individual products and services due to the stratification of those products and services by customers and circumstances. In these instances, we may use information such as geographic region and distribution channel in determining the SSP.