Property, plant and equipment:



	December 31,		December 31,
Net carrying amounts	2018		2017
Building under finance lease	$	5,007	$	5,819
Computer equipment	1,639		1,020
Furniture and fixtures	67		155
Leasehold improvements	1,019		1,624
Production and test equipment	13,888		6,696
	$	21,620	$	15,314



Cost	December 31, 2017		Additions		Disposals			Effect of movements in exchange rates			December 31, 2018
Building under finance lease	$	12,180	$	—	$	—		$	—		$	12,180
Computer equipment	4,787		1,016		(215		)	(4		)	5,584
Furniture and fixtures	1,190		6		(87		)	(6		)	1,103
Leasehold improvements	8,246		71		(363		)	(18		)	7,936
Production and test equipment	36,431		8,932		(2,047		)	(6		)	43,310
	$	62,834	$	10,025	$	(2,712	)	$	(34	)	$	70,113



Accumulated depreciation and impairment loss	December 31, 2017		Depreciation		Disposals			Effect of movements in exchange rates			December 31, 2018
Building under finance lease	$	6,361	$	812	$	—		$	—		$	7,173
Computer equipment	3,767		383		(200		)	(5		)	3,945
Furniture and fixtures	1,035		60		(54		)	(5		)	1,036
Leasehold improvements	6,622		524		(211		)	(18		)	6,917
Production and test equipment	29,735		1,299		(1,607		)	(5		)	29,422
	$	47,520	$	3,078	$	(2,072	)	$	(33	)	$	48,493

During the year ended December 31, 2018, the Corporation had cash additions of $9,854,000 and non-cash additions of $171,000 related to an adjustment for asset retirement obligations (note 16).


9.	Property, plant and equipment (cont'd):



Cost	December 31, 2016		Additions		Disposals			Transfers			Effect of movements in exchange rates		December 31, 2017
Building under finance lease	$	12,180	$	—	$	—		$	—		$	—	$	12,180
Computer equipment	4,607		390		(169		)	(54		)	13		4,787
Furniture and fixtures	1,163		32		(17		)	—			12		1,190
Leasehold improvements	8,794		7		(594		)	—			39		8,246
Production and test equipment	33,053		2,639		(809		)	1,532			16		36,431
Production and test equipment	2,078		—		—			(2,078		)	—		—
under finance lease
	$	61,875	$	3,068	$	(1,589	)	$	(600	)	$	80	$	62,834



Accumulated depreciation and impairment loss	December 31, 2016		Depreciation		Impairment loss		Disposals			Transfers			Effect of movements in exchange rates		December 31, 2017
Building under finance lease	$	5,549	$	812	$	—	$	—		$	—		$	—	$	6,361
Computer equipment	3,558		365		—		(169		)	—			13		3,767
Furniture and fixtures	978		62		—		(17		)	—			12		1,035
Leasehold improvements	6,606		566		—		(594		)	—			44		6,622
Production and test equipment	28,040		1,366		284		(809		)	843			11		29,735
Production and test equipment	1,443		—		—		—			(1,443		)	—		—
under finance lease
	$	46,174	$	3,171	$	284	$	(1,589	)	$	(600	)	$	80	$	47,520

During the year ended December 31, 2018, the Corporation disposed of certain property, plant and equipment totaling $495,000 primarily related to Protonex' Power Manager business (note 27).

Leased assets

The Corporation leases certain assets under finance lease agreements including the Corporation’s head office building in Burnaby, British Columbia (note 17).

Impairment loss

The Corporation recorded an impairment loss on property, plant and equipment of $284,000 in 2017 related to the write-off of certain Protonex Solid Oxide Fuel Cell assets to their estimated net realizable value of $50,000 (note 28).