CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income (loss)	$ 30,473,000	$ (18,853,000)	$ (6,505,000)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation (including capital lease amortization)	6,576,000	6,506,000	6,756,000
Amortization of purchased intangible assets	2,944,000	4,060,000	4,011,000
Amortization and write-off of deferred debt issuance costs	314,000	390,000	156,000
Stock-based compensation	3,580,000	2,975,000	2,326,000
Deferred income tax benefit	(3,653,000)	(556,000)	(284,000)
Loss on disposal of property, plant and equipment	78,000	125,000	455,000
Restructuring and asset impairment expenses	1,114,000	4,283,000	1,202,000
Goodwill impairment charge	0	17,584,000	0
Transition tax liability	(679,000)	946,000	0
Change in:
Accounts receivable, net	(11,409,000)	(14,425,000)	2,679,000
Inventory	(16,610,000)	(5,294,000)	6,829,000
Prepaid expenses and other	491,000	(440,000)	1,002,000
Accounts payable	2,197,000	5,216,000	(1,338,000)
Customer advances	(4,721,000)	3,207,000	223,000
Accrued anti-dumping duties and penalties	4,391,000	(2,941,000)	176,000
Accrued expenses and other liabilities	12,552,000	3,964,000	510,000
Net cash provided by operating activities	27,638,000	6,747,000	18,198,000
Cash flows used in investing activities:
Acquisition of property, plant and equipment	(45,095,000)	(6,186,000)	(5,719,000)
Other investing activities	0	2,000	17,000
Net cash used in investing activities	(45,095,000)	(6,184,000)	(5,702,000)
Cash flows from financing activities:
Borrowings (payments) on revolving loans, net	(1,628,000)	2,000,000	(11,250,000)
Borrowings on capital expenditure facility	25,000,000	0	0
Payment on capital lease obligations	0	0	(4,000)
Payment of dividends	(1,189,000)	(1,174,000)	(1,150,000)
Payment of deferred debt issuance costs	(314,000)	(138,000)	0
Net proceeds from issuance of common stock to employees and directors	442,000	296,000	322,000
Treasury stock purchases	(453,000)	(337,000)	(25,000)
Net cash provided by (used in) financing activities	21,858,000	647,000	(12,107,000)
Effects of exchange rates on cash	(9,000)	1,354,000	(261,000)
Net increase in cash and cash equivalents	4,392,000	2,564,000	128,000
Cash and cash equivalents, beginning of the period	8,983,000	6,419,000	6,291,000
Cash and cash equivalents, end of the period	13,375,000	8,983,000	6,419,000
Cash paid during the period for -
Interest	1,383,000	1,150,000	575,000
Income taxes, net	$ 1,284,000	$ 124,000	$ 354,000