Inventories (Tables)

12 Months Ended

Dec. 31, 2017

Inventory Disclosure [Abstract]

Components of inventory

Inventories are as follows (in thousands):

	December 31,
	2017		2016
Raw materials	$	42,682	$	28,626
Work-in-process	3,284		2,918
Finished goods	29,793		26,739
Inventories	$	75,759	$	58,283

Schedule of inventory reserve

Changes in the reserve for excess and obsolete inventory are as follows (in thousands):

	2017			2016			2015
Balance, beginning of year	$	—		$	—		$	—
Charged to costs and expenses	724			1,301			16
Deductions	(724		)	(1,301		)	(16		)
Balance, end of the year	$	—		$	—		$	—