Revenue Recognition

12 Months Ended

Dec. 31, 2022

Revenue from Contract with Customer [Abstract]

Revenue Recognition

Revenue Recognition

Contract Balances

The following table provides information about accounts receivables, contract assets, customer deposits and deferred revenue from contracts with customers (in thousands):

	December 31,
	2022		2021
Accounts receivable	$	250,995	$	87,788
Contract assets	46,727		25,201
Customer deposits	121,085		64,809
Deferred revenue	94,355		115,476

Contract assets relate to contracts for which revenue is recognized upon transfer of control of performance obligations, however billing milestones have not been reached. Customer deposits and deferred revenue are payments received from customers or invoiced amounts prior to transfer of controls of performance obligations. Customer deposits include $24.6 million related to transactions with SK ecoplant and refundable fees received from customers.

Contract assets and contract liabilities are reported in a net position on an individual contract basis at the end of each reporting period. Contract assets are classified as current in the consolidated balance sheet when both the milestones other than the passage of time are expected to be complete and the customer is invoiced within one year of the balance sheet date, and as long-term when both the above-mentioned milestones are expected to be complete, and the customer is invoiced more than one year out from the balance sheet date. Contract liabilities are classified as current in the consolidated balance sheet when the revenue recognition associated with the related customer payments and invoicing is expected to occur within one year of the balance sheet date and as long-term when the revenue recognition associated with the related customer payments and invoicing is expected to occur in more than one year from the balance sheet date.

Contract Assets

	Years Ended December 31,
	2022		2021
Beginning balance	$	25,201	$	3,327
Transferred to accounts receivable from contract assets recognized at the beginning of the period	(20,250)		(1,198)
Revenue recognized and not billed as of the end of the period	41,776		23,072
Ending balance	$	46,727	$	25,201

Deferred Revenue

Deferred revenue activity, including deferred incentive revenue activity, during the years ended December 31, 2022 and 2021 consisted of the following (in thousands):

	Years Ended December 31,
	2022		2021
Beginning balance	$	115,476	$	135,578
Additions	1,001,404		916,604
Revenue recognized	(1,022,525)		(936,706)
Ending balance	$	94,355	$	115,476

Deferred revenue is equivalent to the total transaction price allocated to the performance obligations that are unsatisfied, or partially unsatisfied, as of the end of the period. The significant component of deferred revenue at the end of the period consists of performance obligations relating to the provision of maintenance services under current contracts and future renewal periods. Some of these obligations provide customers with material rights over a period that we estimate will be largely commensurate with the period of their expected use of the associated Energy Server. As a result, we expect to recognize these amounts as revenue over a period of up to 21 years, predominantly on a relative standalone selling price basis that reflects the cost of providing these services. Deferred revenue also includes performance obligations relating to product acceptance and installation. A significant amount of this deferred revenue is reflected as additions and revenue recognized in the same 12-month period, and a portion of this deferred revenue is expected to be recognized beyond 12-month period mainly due to deployment schedules.

We do not disclose the value of the unsatisfied performance obligations for (i) contracts with an original expected length of one year or less and (ii) contracts for which we recognize revenue at the amount to which we have the right to invoice for services performed.

Disaggregated Revenue

We disaggregate revenue from contracts with customers into four revenue categories: product, installation, services and electricity (in thousands):

	Years Ended December 31,
	2022		2021		2020
Revenue from contracts with customers:
Product revenue	$	880,664	$	663,512	$	518,633
Installation revenue	92,120		96,059		101,887
Services revenue	150,954		144,184		109,633
Electricity revenue	11,608		3,103		1,071
Total revenue from contract with customers	1,135,346		906,858		731,224
Revenue from contracts that contain leases:
Electricity revenue	63,779		65,318		63,023
Total revenue	$	1,199,125	$	972,176	$	794,247