Property and Equipment

3 Months Ended

Mar. 31, 2018

Property, Plant and Equipment [Abstract]

Property and equipment, net, consists of the following (in thousands):



	March 31, 2018			December 30, 2017
Building and building improvements	$	88,215		$	87,999
Machinery and equipment	49,842			47,556
Aircraft and vehicles	25,329			25,329
Land	23,762			23,762
Computer equipment	15,785			15,789
Leasehold improvements	15,649			15,326
Tooling	13,818			13,754
Furniture and office equipment	10,328			9,967
Demonstration units	491			486
Construction-in-progress (CIP)	6,994			6,365
Total property and equipment	250,213			246,333
Accumulated depreciation and amortization	(85,977		)	(82,237		)
Property and equipment, net	$	164,236		$	164,096

For the three months ended March 31, 2018 and April 1, 2017, depreciation expense of property and equipment was $4.0 million and $3.5 million, respectively.

The balances in CIP at March 31, 2018 and December 30, 2017 relate primarily to capitalized costs associated with the implementation of a new enterprise resource planning software system and manufacturing equipment, the underlying assets for which have not been completed or placed into service.