Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net income	$ 2,972	$ 1,536	$ 3,461
Adjustments to reconcile net income to net cash provided by operating activities:
Share-based compensation expense	668	591	512
Change in other receivable	(3)	186	26
Loss (gain) on disposition of long-term assets	16	34	(64)
Depreciation and amortization	$ 2,460	2,555	$ 2,433
Impairment of investment in affiliated company		3,171
Deferred income taxes	$ 457	(147)	$ (533)
Excess tax benefit from employee stock plans	(8)	(80)	(52)
Changes in operating assets and liabilities:
Trade accounts receivable	615	1,727	(1,678)
Other receivables	(194)	(68)	51
Inventories	725	(1,557)	(1,007)
Prepaid income taxes	162	(279)	(139)
Prepaid expenses	61	296	11
Accounts payable	(1,349)	519	292
Accrued compensation and related expenses	71	625	166
Other accrued expenses	84	(18)	(100)
Accrued product warranties	(49)	(32)	88
Accrued income taxes	(205)	211	(15)
Deferred revenue	(111)	400	144
Net cash provided by operating activities	$ 6,372	9,670	3,596
Cash flows from investing activities:
Proceeds from maturities of marketable securities		205	5,501
Purchases of property, plant and equipment	$ (1,617)	(1,349)	(1,513)
Proceeds from sale of property and equipment	56	154	161
Cash paid for intangible assets	(218)	(540)	(951)
Other	96	(3)	(3)
Net cash (used in) provided by investing activities	(1,683)	(1,533)	3,195
Cash flows from financing activities:
Proceeds from the line of credit	21,974	23,552	11,157
Payments on the line of credit	(23,065)	(24,507)	(12,233)
Payments on term notes payable and seller financed note payable	(704)	(2,709)	(2,490)
Proceeds from the exercise of stock options	315	702	772
Excess tax benefit from employee stock plans	8	80	52
Dividends paid	(2,530)	(2,489)	(2,409)
Net cash used in financing activities	(4,002)	(5,371)	(5,151)
Effect of exchange rate changes on cash and cash equivalents	(675)	(567)	78
Net increase in cash and cash equivalents	12	2,199	1,718
Beginning of year	6,332	4,133	2,415
End of year	6,344	6,332	4,133
Supplemental disclosures of cash flow information:
Cash paid during the year for income taxes	1,256	2,184	1,629
Cash paid during the year for interest	124	206	315
Supplemental schedule of noncash investing and financing activities:
Dividends accrued	637	631	619
Purchases of prepaid expenses, fixed assets and intangibles in accounts payable	(109)	(204)	$ (620)
Transfer of inventory to fixed assets	130	$ 18
Purchases of fixed assets in notes payable	162
Transfer of notes payable balance to line of credit	$ 585