10. Fixed Assets

Fixed assets consisted of the following (in thousands):



	Useful Lives	December 31,		December 31,
	(Years)	2017		2016

Leasehold improvements	4-8	$	10,120	$	10,274
Office equipment and furniture	3-15		1,488		2,193
Machinery and laboratory equipment	3-15		2,765		3,255
Software	1-5		3,162		3,581
Construction-in-progress	̶̶̶̶		408		44
			17,943		19,347
Less accumulated depreciation and amortization			(13,651)		(13,920)
Fixed assets, net		$	4,292	$	5,427

Depreciation and amortization of fixed assets totaled $1.8 million, $2.3 million and $2.3 million in each of the years ended December 31, 2017, 2016 and 2015, respectively. The construction‑in‑progress balance was related to costs of unimplemented software still under development. Unamortized computer software costs were $0.2 million and $0.8 million at December 31, 2017 and 2016, respectively. The amortization of computer software costs amounted to $0.6 million, $0.7 million and $0.7 million during the years ended December 31, 2017, 2016 and 2015, respectively.

During the first quarter of 2017, the Company disposed of $2.1 million of fully depreciated assets. There was no consideration received for the disposal of these assets and the disposal did not have a significant impact on the consolidated financial statements of the Company.