3. REVENUE

The Company’s disaggregated revenues are represented by the two reportable segments discussed in Note 17.

The contract balances include the following (in thousands):

Accounts receivable are recorded at the amount invoiced, net of an allowance for doubtful accounts, sales returns, and sales incentives. Payment terms can vary by customer and contract.

The timing of revenue recognition may differ from the timing of invoicing to customers. Contract assets are created when invoicing occurs subsequent to revenue recognition. Contract assets are transferred to accounts receivable when the right to invoice becomes unconditional. The Company’s contract assets are generally current in nature and are included in Prepaid expenses and other current assets. Contract assets increased by $3.8 million during the year ended December 31, 2020 and by $2.8 million during the year ended December 31, 2019 primarily due to an increase in the growth of platform revenue combined with the timing of billing which falls into a subsequent period.

Contract liabilities are included in deferred revenue and reflect consideration invoiced prior to the completion of performance obligations and revenue recognition. Deferred revenue increased by approximately $21.5 million during the year ended December 31, 2020 due to the increase in estimated values of content publisher and licensing partner arrangements and change in the timing of fulfillment of performance obligations of approximately $12.4 million, and higher growth in the player segment, resulting in a net increase in deferred revenue related to unspecified upgrades of approximately $8.4 million. Deferred revenue decreased by approximately $9.8 million during the year ended December 31, 2019 primarily due to revenue recognized of $5.0 million pursuant to customer acceptance of a milestone, and the remaining revenue recognized primarily relates to the timing of fulfillment of performance obligations.

Revenue recognized during the year ended December 31, 2020 from amounts included in deferred revenue as of December 31, 2019 was $42.9 million. Revenue recognized during the year ended December 31, 2019 from amounts included in deferred revenue as of December 31, 2018 was $52.5 million.

Revenue allocated to remaining performance obligations represents estimated contracted revenue that has not yet been recognized which includes unearned revenue and amounts that will be invoiced and recognized as revenue in future periods. Estimated contracted revenue was $513.7 million as of December 31, 2020 of which the Company expects to recognize approximately 55% over the next 12 months and the remainder thereafter.

The Company recognized $14.4 million and $10.9 million during the years ended December 31, 2020 and 2019, respectively, from performance obligations that were satisfied in previous periods due to the changes in transaction price of its revenue contracts.

Customer C accounted for 12%, 14% and 18% of the total net revenue during the years ended December 31, 2020, 2019 and 2018, respectively.