5.	Inventories

(Table only in thousands)	June 30, 2018			December 31, 2017
Raw materials	$	16,561		$	18,444
Work in process		6,633			3,182
Finished goods		773			940
Obsolescence allowance		(1,517	)		(1,597	)
Total inventories	$	22,450		$	20,969

Amounts credited to the allowance for obsolete inventory and charged to cost of sales amounted to $0.1 million and $0.2 million for the three-month periods ended June 30, 2018 and 2017, respectively, and $0.4 million and $0.3 million for the six-month periods ended June 30, 2018 and 2017, respectively.