Property, Plant and Equipment

Property, plant and equipment are recorded at historical cost, net of accumulated depreciation. Components of property, plant and equipment, net are summarized as follows:



	As of December 31,
(In millions)	2017			2016
Land	$	141.2		$	137.8
Buildings	1,213.6			1,107.8
Leasehold improvements	80.6			123.7
Machinery and equipment	1,207.7			1,105.8
Computer software and hardware	767.1			746.8
Furniture and fixtures	55.3			60.6
Construction in progress	1,276.0			658.6
Total cost	4,741.5			3,941.1
Less: accumulated depreciation	(1,559.1		)	(1,439.3		)
Total property, plant and equipment, net	$	3,182.4		$	2,501.8

Depreciation expense totaled $266.3 million, $309.3 million and $217.9 million for 2017, 2016 and 2015, respectively.

For 2017, 2016 and 2015, we capitalized interest costs related to construction in progress totaling approximately $30.7 million, $12.9 million and $10.4 million, respectively. The increase in capitalized interest costs is primarily due to the construction of our Solothurn, Switzerland facility, as discussed below.

Solothurn, Switzerland Facility

During the first quarter of 2016 we purchased land in Solothurn, Switzerland for 64.4 million Swiss Francs (approximately $62.5 million) and are building a large-scale biologics manufacturing facility at this site. We expect this facility to be operational by the end of the decade. Upon completion, the facility will include 393,000 square feet related to a large-scale biologics manufacturing facility, 290,000 square feet of warehouse, utilities and support space and 51,000 square feet of administrative space. As of December 31, 2017 and 2016, we had approximately $1.2 billion and $481.5 million, respectively, capitalized as construction in progress related to this facility.

Research Triangle Park Facility Purchase

In August 2015 we completed the purchase of a drug product manufacturing facility and supporting infrastructure in Research Triangle Park (RTP), NC from Eisai Inc. (Eisai). The $104.8 million purchase price was comprised of $58.6 million for buildings, $25.9 million for machinery and equipment and $20.3 million for land.

In August 2015 we also amended our existing 10-year lease related to Eisai's oral solid dose products manufacturing facility in RTP, NC. The amended lease provided for a three-year term and our agreement to purchase the facility upon expiration of the lease term or at Eisai's option, their completion of certain activities at the facility. Upon signing, we recognized assets along with a corresponding financing obligation in our consolidated balance sheet of $20.3 million, the net present value of the future minimum lease payments. These assets were recorded as a component of buildings and machinery and equipment. In December 2017, upon the earlier than expected completion of Eisai's activities, we completed our purchase of this facility for $17.2 million.