CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets
Accounts receivable, reserve	$ 388	$ 411
Inventories, obsolescence reserve	927	1,484
Property and equipment, accumulated depreciation	$ 27,148	$ 25,841

Amount of valuation reserve for inventory.

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Name:	us-gaap_InventoryValuationReserves
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant