Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Income from continuing operations	$ 9,147	$ 10,751
Loss from discontinued operations	(160)	(1,169)
Net income	8,987	9,582
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	4,468	4,518
Provision (recovery) of allowance for doubtful accounts	(39)	221
Inventory lower-of-cost-or-market/NRV adjustments	179	258
Stock-based compensation expense	747	1,130
Loss on asset dispositions	1	0
Deferred income taxes, net of valuation allowance	1,323	67
Other	23	(65)
Changes in operating assets and liabilities:
Trade receivables	17,506	20,982
Inventories	10,821	4,226
Prepaids and other current assets	(734)	2,141
Income taxes receivable	(4,115)	(809)
Trade payables	(20,659)	(19,477)
Accrued liabilities, including warranty obligations	(1,919)	(4,897)
Net cash provided by operating activities	16,589	17,877
Cash flows from investing activities:
Purchases of available-for-sale securities	(29,522)	(53,573)
Proceeds from maturities of available-for-sale securities	26,815	21,735
Purchases of property, plant and equipment	(4,228)	(1,084)
Net cash used in investing activities	(6,935)	(32,922)
Cash flows from financing activities:
Payments on long-term debt	(8,000)	(8,000)
Payments for stock repurchases	(3,127)	(3,427)
Proceeds from exercise of stock options	492	490
Tax payments related to stock award issuances	(396)	(741)
Net cash used in financing activities	(11,031)	(11,678)
Effect of exchange rate changes on cash and cash equivalents	(587)	660
Decrease in cash and cash equivalents	(1,964)	(26,063)
Cash and cash equivalents:
Beginning of period	27,893	47,874
End of period	25,929	21,811
Supplemental disclosure of cash flow information:
Cash paid for interest	558	851
Cash paid for income taxes, net	6,366	5,289
Supplemental disclosure of non-cash investing activities:
Capital expenditures incurred but not yet paid	$ 437	$ 338