Revenue (Tables)

3 Months Ended

Mar. 31, 2020

The following table provides information about disaggregation of revenue (in thousands):


Major products/services lines
	Three months ended March 31,
	2020		2019
Sales of fuel cell systems	$	14,651	$	1,241
Sale of hydrogen installations and other infrastructure		5,736		1,303
Services performed on fuel cell systems and related infrastructure		6,521		6,343
Power Purchase Agreements		6,496		6,110
Fuel delivered to customers		7,333		6,582
Other		76		—
Net revenue	$	40,813	$	21,579

Schedule of receivables, contract assets and contract liabilities from contracts with customers

The following table provides information about receivables, contract assets and contract liabilities from contracts with customers (in thousands):


	March 31,		December 31,
	2020		2019
Accounts receivable	$	24,437	$	25,448
Contract assets		20,581		13,251
Contract liabilities		45,129		43,480

Schedule of changes in contract assets and the contract liabilities

Significant changes in the contract assets and the contract liabilities balances during the period are as follows (in thousands):



Contract assets	Three months ended
	March 31, 2020
Transferred to receivables from contract assets recognized at the beginning of the period	$	(141)
Revenue recognized and not billed as of the end of the period		7,471
Net change in contract assets		7,330

Schedule of Estimated future revenue

The following table includes estimated revenue expected to be recognized in the future (sales of fuel cell systems and hydrogen installations are expected to be recognized as revenue within one year; sales of services and PPAs are expected to be recognized as revenue over five to seven years) related to performance obligations that are unsatisfied (or partially unsatisfied) at the end of the reporting period, excluding provision for common stock warrants as it is not readily estimable as it depends on the valuation of the common stock warrants when revenue is recognized (in thousands):



	March 31,
	2020
Sales of fuel cell systems	$	76,433
Sale of hydrogen installations and other infrastructure		69,440
Services performed on fuel cell systems and related infrastructure		97,530
Power Purchase Agreements		142,002
Other rental income		4,531
Total estimated future revenue	$	389,936