Property, Plant and Equipment, and Leases

12 Months Ended

Dec. 31, 2018

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment, and Leases

Property, Plant and Equipment, and Leases

Property, plant and equipment by type were as follows:

(in thousands)	As of December 31,
Property, Plant and Equipment	2018			2017
Leasehold improvements	$	6,405		$	6,320
Machinery and equipment	38,454			27,379
Construction in progress	1,241			2,036
Total property, plant and equipment, at cost	46,100			35,735
Accumulated depreciation	(21,834		)	(16,775		)
Property, plant and equipment, net	$	24,266		$	18,960

In April 2018, the Company finalized the purchase of emissions testing assets and the sublease of an emissions testing facility from Ricardo, Inc., a subsidiary of the strategic engineering and environmental consultancy, Ricardo Plc., for $5.6 million in cash. The Company accounted for the acquisition as an asset acquisition and recorded property, plant and equipment of $6.9 million, included within machinery and equipment in the table above, and an asset retirement obligation of $1.3 million as a result of the transaction. The fair value of the asset retirement obligation was estimated using Level 3 inputs. The asset retirement obligation is recorded in Other non-current liabilities in the Company’s Consolidated Balance Sheet.

Leases

The Company leases certain buildings and equipment under various non-cancelable operating leases and a capital lease. Rent expense under operating leases approximated $5.1 million and $4.7 million for 2018 and 2017, respectively. Rent expense is recorded on a straight-line basis over the period of the lease term. The Company recognized the capital lease obligation of $0.4 million and related leased equipment based on the present value of the minimum lease payments at lease inception.

The future minimum lease payments due under operating and capital leases in effect, as amended and extended, as of December 31, 2018, were as follows:

	Year Ending December 31,
(in thousands)	Operating		Capital
2019	$	5,071	$	80
2020	5,175		63
2021	4,724		67
2022	4,681		50
2023	3,104		13
2024 and beyond	3,694		—
Total	$	26,449	$	273