CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (18,853,000)	$ (6,505,000)	$ (23,971,000)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation (including capital lease amortization)	6,506,000	6,756,000	6,244,000
Amortization of purchased intangible assets	4,060,000	4,011,000	4,033,000
Amortization and write-off of deferred debt issuance costs	390,000	156,000	752,000
Stock-based compensation	2,975,000	2,326,000	2,826,000
Deferred income tax benefit	(556,000)	(284,000)	(725,000)
(Gain) loss on disposal of property, plant and equipment	125,000	455,000	(23,000)
Restructuring and asset impairment expenses	4,283,000	1,202,000	4,063,000
Goodwill impairment charge	17,584,000	0	11,464,000
Transition tax liability	946,000	0	0
Other	0	0	23,000
Change in:
Accounts receivable, net	(14,425,000)	2,679,000	(2,394,000)
Inventory, net	(5,294,000)	6,829,000	1,386,000
Prepaid expenses and other	(440,000)	1,002,000	(3,570,000)
Accounts payable	5,216,000	(1,338,000)	758,000
Customer advances	3,207,000	223,000	(857,000)
Accrued anti-dumping duties	(2,941,000)	176,000	6,374,000
Accrued expenses and other liabilities	3,964,000	510,000	(4,765,000)
Net cash provided by operating activities	6,747,000	18,198,000	1,618,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisition of property, plant and equipment	(6,186,000)	(5,719,000)	(5,433,000)
Proceeds on sale of property, plant and equipment	2,000	26,000	0
Change in other non-current assets	0	(9,000)	107,000
Net cash used in investing activities	(6,184,000)	(5,702,000)	(5,326,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Borrowings (payments) on lines of credit	2,000,000	(11,250,000)	5,003,000
Payment on capital lease obligations	0	(4,000)	(5,000)
Payment of dividends	(1,174,000)	(1,150,000)	(2,260,000)
Payment of deferred debt issuance costs	(138,000)	0	(1,222,000)
Net proceeds from issuance of common stock to employees and directors	296,000	322,000	272,000
Treasury stock purchases	(337,000)	(25,000)	0
Net cash provided by (used in) financing activities	647,000	(12,107,000)	1,788,000
EFFECTS OF EXCHANGE RATES ON CASH	1,354,000	(261,000)	(1,189,000)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	2,564,000	128,000	(3,109,000)
CASH AND CASH EQUIVALENTS, beginning of the period	6,419,000	6,291,000	9,400,000
CASH AND CASH EQUIVALENTS, end of the period	8,983,000	6,419,000	6,291,000
Cash paid during the period for -
Interest	1,150,000	575,000	624,000
Income taxes, net	$ 124,000	$ 354,000	$ 2,491,000