Balance Sheet Components

Inventories

The components of inventory consisted of the following (in thousands):



	March 31, 2020		December 31, 2019

Raw materials	$	59,099	$	67,829
Work-in-progress	18,564		21,207
Finished goods	29,541		20,570
	$	107,204	$	109,606

The inventory reserves were $14.9 million and $14.6 million as of March 31, 2020 and December 31, 2019, respectively.

Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consisted of the following (in thousands):



	March 31, 2020		December 31, 2019

Government incentives receivable	$	839	$	893
Prepaid production insurance	3,961		3,763
Receivables from employees	6,653		6,130
Other prepaid expenses and other current assets	13,541		17,282
	$	24,994	$	28,068

Property, Plant and Equipment, Net

Property, plant and equipment, net consisted of the following (in thousands):



	March 31, 2020			December 31, 2019

Energy Servers	$	648,273		$	650,600
Computers, software and hardware	20,453			20,275
Machinery and equipment	102,837			101,650
Furniture and fixtures	8,309			8,339
Leasehold improvements	35,694			35,694
Building	40,512			40,512
Construction in progress	22,854			12,611
	878,932			869,681
Less: Accumulated depreciation	(272,082		)	(262,622		)
	$	606,850		$	607,059

Construction in progress increased $10.2 million from 2019, primarily due to an increase of $8.4 million of Energy Servers under our Managed Services sale-leaseback program pending acceptance, and increased $1.8 million primarily due to Delaware plant expansion.

Depreciation expense related to property, plant and equipment was $13.0 million and $13.9 million for the three months ended March 31, 2020 and 2019, respectively.

Property, plant and equipment under operating leases by the PPA Entities was $368.0 million and $371.4 million as of March 31, 2020 and December 31, 2019, respectively. The accumulated depreciation for these assets was $98.3 million and $95.5 million as of March 31, 2020 and December 31, 2019, respectively. Depreciation expense related to our property, plant and equipment under operating leases by the PPA Entities was $6.2 million and $6.4 million for the three months ended March 31, 2020 and 2019, respectively.

Customer Financing Receivable

The components of investment in sales-type financing leases consisted of the following (in thousands):



	March 31, 2020			December 31, 2019
Total minimum lease payments to be received	$	74,955		$	76,886
Less: Amounts representing estimated executing costs	(19,344		)	(19,931		)
Net present value of minimum lease payments to be received	55,611			56,955
Estimated residual value of leased assets	890			890
Less: Unearned income	(1,885		)	(1,990		)
Net investment in sales-type financing leases	54,616			55,855
Less: Current portion	(5,170		)	(5,108		)
Non-current portion of investment in sales-type financing leases	$	49,446		$	50,747

The future scheduled customer payments from sales-type financing leases were as follows as of March 31, 2020 (in thousands):



	Remainder of 2020		2021		2022		2023		2024		Thereafter

Future minimum lease payments, less interest	$	3,868	$	5,428	$	5,784	$	6,155	$	6,567	$	25,923

Other Long-Term Assets

Other long-term assets consisted of the following (in thousands):



	March 31, 2020		December 31, 2019

Prepaid and other long-term assets	$	31,134	$	29,153
Deferred commissions	5,668		5,007
Equity-method investments	5,897		5,733
Long-term deposits	1,897		1,759
	$	44,596	$	41,652

Accrued Warranty

Accrued warranty liabilities consisted of the following (in thousands):



	March 31, 2020		December 31, 2019

Product warranty	$	2,566	$	2,345
Product performance	6,940		7,536
Maintenance services contracts	1,508		453
	$	11,014	$	10,334

Changes in the product warranty and product performance liabilities were as follows (in thousands):



Balances at December 31, 2019	$	9,881
Accrued warranty, net	514
Warranty expenditures during period	(889		)
Balances at March 31, 2020	$	9,506

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following (in thousands):



	March 31, 2020		December 31, 2019

Compensation and benefits	$	17,611	$	17,173
Current portion of derivative liabilities	6,434		4,834
Sales related liabilities	391		416
Accrued installation	10,923		10,348
Sales tax liabilities	3,899		3,849
Interest payable	2,880		3,875
Accrued payables	24,860		18,650
Other	10,811		11,139
	$	77,809	$	70,284

Other Long-Term Liabilities

Other long-term liabilities consisted of the following (in thousands):



	March 31, 2020		December 31, 2019

Delaware grant	$	10,469	$	10,469
Other	18,074		17,544
	$	28,543	$	28,013

In March 2012, we entered into an agreement with the Delaware Economic Development Authority to provide a grant of $16.5 million to us as an incentive to establish a new manufacturing facility in Delaware and to provide employment for full time workers at the facility over a certain period of time. We have received $12.0 million of the grant which is contingent upon us meeting certain milestones related to the construction of the manufacturing facility and the employment of full-time workers at the facility through September 30, 2023. We paid $1.5 million in 2017 for recapture provisions, and no additional amounts have been paid. As of March 31, 2020, we have recorded $10.5 million in other long-term liabilities for potential repayments. See Note 14, Commitments and Contingencies for a full description of the grant.