Revenue Recognition

6 Months Ended

Jun. 30, 2021

Revenue from Contract with Customer [Abstract]

Revenue Recognition

Revenue Recognition

Contract Balances

The following table provides information about contract balances from contracts with customers (in thousands):

	June 30,		December 31,
	2021		2020
Accounts receivable	$	54,468	$	96,186
Contract assets	18,638		3,327
Customer deposits	42,066		66,171
Deferred revenue	116,255		135,578

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 are refundable fees until certain milestones are met.

Contract Assets

During the three months ended June 30, 2021, contract assets increased from $5.0 million to $18.6 million. Contract assets of $14.2 million were recognized during this period as the related performance obligations were satisfied but the billing milestones had not been met. During this period, we billed $0.6 million that was included in the contract assets balance as of March 31, 2021.

During the six months ended June 30, 2021, contract assets increased from $3.3 million to $18.6 million. Contract assets of $15.3 million were recognized during this period as the related performance obligations were satisfied but the billing milestones had not been met. During this period, we did not bill any amounts that were included in the contract assets balance as of December 31, 2020.

Deferred Revenue

Deferred revenue activity, including deferred incentive revenue activity, during the three and six months ended June 30, 2021 and 2020 consists of the following (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Beginning balance	$	120,643	$	177,266	$	135,578	$	175,455
Additions	195,324		159,244		350,785		297,631
Revenue recognized	(199,712)		(167,257)		(370,108)		(303,833)
Ending balance	$	116,255	$	169,253	$	116,255	$	169,253

Disaggregated Revenue

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Revenue from contracts with customers:
Product revenue	$	146,867	$	116,197	$	284,797	$	215,756
Installation revenue	28,879		29,839		31,538		46,457
Services revenue	35,707		26,208		72,124		51,355
Electricity revenue	707		72		1,302		144
Total revenue from contract with customers	212,160		172,316		389,761		313,712
Revenue from contracts accounted for as leases:
Electricity revenue	16,310		15,540		32,716		30,843
Total revenue	$	228,470	$	187,856	$	422,477	$	344,555