Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Statement Of Cash Flows [Abstract]
Net cash flows used in operating activities - continuing operations	$ (8,165)	$ (5,206)
Cash flows from investing activities:
Purchases of property, plant and equipment	(3,761)	(4,321)
Purchases of long-term marketable securities	(47)	(91)
Proceeds from sale of long-term marketable securities	169	186
Net cash flows used in investing activities - continuing operations	(3,639)	(4,226)
Cash flows from financing activities:
Repayment of debt	(27,627)	(496)
Proceeds from Revolving Credit and Security Agreement	32,956	19,971
Payments on Revolving Credit and Security Agreement	(6,000)	0
Dividends paid	(7)	(35)
Funding of discontinued operations	(567)	(6,946)
Net cash flows (used in) provided by financing activities - continuing operations	(1,245)	12,494
Effect of exchange rate changes on cash and cash equivalents	(208)	(803)
Cash flows from discontinued operations:
Net cash flows used in operating activities - discontinued operations	(645)	(6,144)
Net cash flows used in investing activities - discontinued operations	(98)	(1,613)
Net cash flows provided by financing activities - discontinued operations	567	6,946
Net cash flows used in discontinued operations	(176)	(811)
Net (decrease) increase in cash and cash equivalents	(13,433)	1,448
Cash and cash equivalents at beginning of period	20,837	20,700
Cash and cash equivalents at end of period	7,404	22,148
Less: cash and cash equivalents of discontinued operations	(948)	(1,233)
Cash and cash equivalents	6,456	20,915
Supplemental information:
Income tax payments	657	918
Interest payments	1,611	830
Non-cash investing and financing activities:
Purchases of property, plant and equipment included in accounts payable	1,511	1,200
Finance lease right-of-use assets exchanged for lease liabilities	$ 555	$ 0