FIXED ASSETS

9 Months Ended

Sep. 30, 2021

Property, Plant and Equipment [Abstract]

Fixed assets, net, summarized by major category, consist of the following (in thousands):


	September 30,		December 31,
	2021		2020
Machinery and equipment	$	111,819	$	74,966
Leasehold improvements	60,426		54,434
Computer equipment and software	12,744		12,170
Office furniture and equipment	2,477		2,387
Construction in progress	59,579		71,091
Total	247,045		215,048
Less: accumulated depreciation	(87,810)		(78,360)
Fixed assets, net	$	159,235	$	136,688

For the three months ended September 30, 2021 and 2020, depreciation expense was $3.8 million and $3.1 million, respectively. For the three months ended September 30, 2021 and 2020, there was $0.9 million and $0.7 million of capitalized interest on the construction of manufacturing sites, respectively.

For the nine months ended September 30, 2021 and 2020, depreciation expense was $9.6 million and $8.9 million, respectively. For the nine months ended September 30, 2021 and 2020, there was $3.0 million and $1.5 million of capitalized interest on the construction of manufacturing sites, respectively.

At September 30, 2021 and December 31, 2020, total fixed assets, net includes leasehold improvements and manufacturing process equipment located in Europe in the amount of $66.9 million and $67.5 million, respectively.

As of September 30, 2021 and December 31, 2020, the Company had asset retirement obligations of $2.1 million and $2.0 million, respectively, which are included in accrued expenses and other liabilities on its condensed consolidated balance

sheet, for costs associated with returning leased spaces to their original condition upon the termination of certain lease agreements.