Revenue

Disaggregation of Revenue

The following table summarizes net sales by end market:



(in thousands)	For the Three Months Ended June 30,				For the Six Months Ended June 30,
End Market	2020		2019		2020		2019
Energy	$	29,649	$	52,245	$	79,733	$	97,893
Industrial	30,463		54,660		67,594		105,247
Transportation	32,944		31,779		50,826		51,331
Total	$	93,056	$	138,684	$	198,153	$	254,471

The following table summarizes net sales by geographic area:



(in thousands)	For the Three Months Ended June 30,				For the Six Months Ended June 30,
Geographic Area	2020		2019		2020		2019
North America	$	81,979	$	119,943	$	176,499	$	217,622
Pacific Rim	6,295		10,804		12,749		23,429
Europe	2,578		5,006		5,235		8,383
Other	2,204		2,931		3,670		5,037
Total	$	93,056	$	138,684	$	198,153	$	254,471

Contract Balances

Most of the Company’s contracts are for a period of less than one year; however, certain long-term manufacturing and extended warranty contracts extend beyond one year. The timing of revenue recognition may differ from the time of invoicing to customers and these timing differences result in contract assets or contract liabilities on the Company’s Consolidated Balance Sheets. Contract assets include amounts related to the contractual right to consideration for completed performance when the right to consideration is conditional. The Company records contract liabilities when cash payments are received or due in advance of performance. Contract assets and contract liabilities are recognized at the contract level.



(in thousands)	As of June 30, 2020			As of December 31, 2019
Short-term contract assets (included in Prepaid expenses and other current assets)	$	2,340		$	694
Short-term contract liabilities (included in Other accrued liabilities)	(52,412		)	(26,898		)
Long-term contract liabilities (included in Noncurrent contract liabilities)	(3,062		)	(17,998		)
Net contract liabilities	$	(53,134	)	$	(44,202	)

During the six months ended June 30, 2020 and 2019, the Company recognized $4.8 million and $3.7 million, respectively, of revenue upon satisfaction of performance obligations related to amounts that were included in the net contract liabilities balance as of December 31, 2019 and 2018, respectively. The increase in the contract asset during the six months ended June 30, 2020 is related to performance completed and revenue recognized under certain contracts but for which the Company’s right to consideration is conditional at the end of the period. The increase in the contract liabilities during the six months ended June 30, 2020 is primarily related to prepayments for certain engines by a customer under a long-term supply agreement.

Remaining Performance Obligations

For performance obligations that extend beyond one year, the Company had $54.9 million of remaining performance obligations as of June 30, 2020 which primarily relates to prepayments for certain engines by a customer under a long-term supply agreement. The Company expects to recognize revenue related to these remaining performance obligations of approximately $27.0 million in the remainder of 2020, $25.2 million in 2021, $0.7 million in 2022, $0.8 million in 2023, $0.8 million in 2024 and $0.4 million in 2025 and beyond.