Inventories, net

Inventories, net consists of the following:


	As of
	September 30,		December 31,
	2019		2018
	(Amounts in thousands)
Raw materials	$	29,197	$	24,937
Work-in-process		5,438		5,185
Finished products		16,944		12,141

Total inventories, net	$	51,579	$	42,263

Property, Plant and Equipment

Property, plant and equipment consist of the following:


	As of
	September 30,			December 31,
	2019			2018
	(Amounts in thousands)
Land	$	1,023		$	1,023
Buildings		764			764
Leasehold improvements		22,953			16,259
Equipment		31,144			24,092
Furniture and fixtures		14,214			5,448
Construction in progress (1)		5,721			12,906
Other		50			—

Total property, plant and equipment		75,869			60,492
Less—Accumulated depreciation		(32,835	)		(28,312	)

Total property, plant and equipment, net	$	43,034		$	32,180

(1)

Construction in progress as of September 30, 2019

includes $4.9 million

, which is

primarily

related to various manufacturing expansion projects at our Waltham

, Massachusetts

and Rancho

Dominguez, California

facilities.

Construction in progress as of December 31, 2018 includes $

2.1

million of capitalized

internal-use

software development costs and $

7.3

million for the buildout of our Marlborough

, Massachusetts

facility. Both projects have since been placed into service

and as a result

, $6.5 million of internal-use software development costs are now included in furniture and fixtures as of September 30, 2019

Depreciation expenses totaled $1.8 million and $1.3 million for the three months ended September 30, 2019 and 2018, respectively. Depreciation expenses totaled $5.2 million and $3.9 million for the nine months ended September 30, 2019 and 2018, respectively.

Accrued Liabilities

Accrued liabilities consist of the following:


	As of
	September 30,		December 31,
	2019		2018
	(Amounts in thousands)
Employee compensation	$	14,451	$	9,953
Taxes		3,071		1,024
Royalty and license fees		707		242
Warranties		1,255		546
Professional fees		715		942
Deferred revenue		4,286		1,290
Other		1,285		1,868

Total accrued liabilities	$	25,770	$	15,865