Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement Of Cash Flows [Abstract]
Net cash flows used in operating activities - continuing operations	$ (7,089)	$ (9,600)
Cash flows from investing activities:
Purchases of property, plant and equipment	(1,379)	(1,453)
Purchases of long-term marketable securities	(12)	(89)
Proceeds from sale of long-term marketable securities	80	128
Net cash flows used in investing activities - continuing operations	(1,311)	(1,414)
Cash flows from financing activities:
Repayment of debt	(27,080)	(178)
Proceeds from Revolving Credit and Security Agreement	29,217	16,052
Payments on Revolving Credit and Security Agreement	(3,500)	0
Funding of discontinued operations	573	(2,256)
Net cash flows (used in) provided by financing activities - continuing operations	(790)	13,618
Effect of exchange rate changes on cash and cash equivalents	(80)	142
Cash flows from discontinued operations:
Net cash flows provided by (used in) operating activities - discontinued operations	108	(1,252)
Net cash flows used in investing activities - discontinued operations	(264)	(1,496)
Net cash flows (used in) provided by financing activities - discontinued operations	(573)	2,256
Net cash flows used in discontinued operations	(729)	(492)
Net (decrease) increase in cash and cash equivalents	(9,999)	2,254
Cash and cash equivalents at beginning of period	20,837	20,700
Cash and cash equivalents at end of period	10,838	22,954
Less: cash and cash equivalents of discontinued operations	(395)	(1,552)
Cash and cash equivalents	10,443	21,402
Supplemental information:
Income tax payments	212	82
Interest payments	370	240
Non-cash investing and financing activities:
Purchases of property, plant and equipment included in accounts payable	780	737
Finance lease right-of-use assets exchanged for lease liabilities	$ 453	$ 0