Property, Plant and Equipment

6 Months Ended

Jun. 30, 2019

Property, Plant and Equipment [Abstract]

Property, plant and equipment by type were as follows:



(in thousands)	As of June 30,			As of December 31,
Property, Plant and Equipment	2019			2018
Leasehold improvements	$	6,475		$	6,405
Machinery and equipment	39,851			38,454
Construction in progress	1,150			1,241
Total property, plant and equipment, at cost	47,476			46,100
Accumulated depreciation	(24,040		)	(21,834		)
Property, plant and equipment, net	$	23,436		$	24,266

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 noncurrent liabilities in the Company’s Consolidated Balance Sheets.