Revenue Recognition

12 Months Ended

Dec. 31, 2021

Revenue from Contract with Customer [Abstract]

Revenue Recognition

Revenue Recognition

The following table summarizes disaggregated revenue information by geographic area based on the customer's country of domicile (in thousands):

	Year Ended December 31,
	2021		2020		2019
Americas	$	435,220	$	310,027	277,155
Europe	247,744		208,787		227,738
Greater China	200,135		168,287		115,061
Other Asia	153,999		123,919		105,671
	$	1,037,098	$	811,020	$	725,625

The following table summarizes disaggregated revenue information by revenue type (in thousands):

	Year Ended December 31,
	2021		2020		2019
Standard products and services	$	889,253	$	674,830	$	629,220
Application-specific customer solutions	147,845		136,190		96,405
	$	1,037,098	$	811,020	$	725,625

Costs to Fulfill a Contract

Costs to fulfill a contract are included in "Prepaid expenses and other current assets" on the Consolidated Balance Sheets and amounted to $10,854,000 and $6,846,000 as of December 31, 2021 and 2020, respectively.

Accounts Receivable, Contract Assets, and Contract Liabilities

Accounts receivable represent amounts billed and currently due from customers which are reported at their net estimated realizable value. The Company maintains an allowance against its accounts receivable for credit losses. Contract assets consist of unbilled revenue which arises when revenue is recognized in advance of billing for certain application-specific customer solutions contracts. Contract liabilities consist of deferred revenue and customer deposits which arise when amounts are billed to or collected from customers in advance of revenue recognition.

The following table summarizes changes in the allowance for credit losses (in thousands):

	Amount
Balance as of December 31, 2019	$	530
Increases to the allowance for credit losses	600
Write-offs, net of recoveries	(300)
Foreign exchange rate changes	1
Balance as of December 31, 2020	831
Increases to the allowance for credit losses	—
Write-offs, net of recoveries	(55)
Foreign exchange rate changes	—
Balance as of December 31, 2021	$	776

The Company's higher estimate of expected credit losses in 2020 took into account the global economic conditions resulting from the COVID-19 pandemic.

The following table summarizes the deferred revenue and customer deposits activity (in thousands):

	Amount
Balance as of December 31, 2019	$	14,432
Deferral of revenue billed in the current period, net of recognition	19,014
Recognition of revenue deferred in prior period	(12,443)
Foreign exchange rate changes	271
Balance as of December 31, 2020	21,274
Deferral of revenue billed in the current period, net of recognition	31,907
Recognition of revenue deferred in prior period	(17,403)
Foreign exchange rate changes	(35)
Balance as of December 31, 2021	$	35,743

As a practical expedient, the Company has elected not to disclose the aggregate amount of the transaction price allocated to unsatisfied performance obligations, as our contracts have an original expected duration of less than one year.