Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Income from continuing operations	$ 5,748	$ 5,524
Loss from discontinued operations	(374)	(365)
Net income	5,374	5,159
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	865	818
Bad debt expense	30	169
Inventory lower-of-cost-or-market adjustments	589	0
Stock-based compensation expense	265	214
Loss on asset dispositions	1	14
Deferred income taxes, net of valuation allowance	2,321	257
Excess tax deficiency related to stock-based awards	102	0
Changes in operating assets and liabilities:
Trade receivables, net	11,752	9,280
Inventories	1,765	5,130
Prepaids and other current assets	2,617	1,498
Income taxes payable	356	(105)
Trade payables	(9,830)	(14,968)
Accrued liabilities, including warranty obligations	(1,085)	(1,431)
Net cash provided by operating activities	15,122	6,035
Cash flows from investing activities:
Purchase of marketable securities	(13,518)	0
Proceeds from sale of assets of discontinued operations	0	96
Purchases of property, plant and equipment	(521)	(762)
Net cash used in investing activities	(14,039)	(666)
Cash flows from financing activities:
Proceeds from exercise of stock options	42	147
Excess tax deficiency related to stock-based awards	(102)	0
Net cash provided by (used in) financing activities	(60)	147
Effect of exchange rate changes on cash and cash equivalents	33	(43)
Increase in cash and cash equivalents	1,056	5,473
Cash and cash equivalents:
Beginning of period	40,979	23,207
End of period	42,035	28,680
Supplemental disclosure of cash flow information:
Cash paid for interest	7	10
Cash paid for income taxes, net	$ 95	$ 109