Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating activities
Net income	$ 650	$ 2,597
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Inventories allowances	21	99
Deferred tax expense	353	972
Depreciation and amortization	727	718
Share-based and stock compensation expense	34	42
Restricted stock unit compensation expense	41	0
Realized tax benefit from stock option exercise	0	393
Gain on available-for-sale securities	(1,287)	0
Loss on disposal of property, plant and equipment	94	0
Changes in operating assets and liabilities:
Trade accounts receivable	(3,584)	(2,115)
Inventories	(1,257)	2,899
Prepaid expenses and other current assets	567	1,260
Other assets	(12)	(7)
Accounts payable	3,803	526
Accrued compensation and related taxes	(943)	803
Accrued warranty expense	545	48
Deferred revenue	52	36
Customer deposits	0	2
Accrued other expenses and other current liabilities	(49)	33
Net cash (used in) provided by operating activities	(245)	8,306
Investing activities
Purchases of property, plant and equipment	(572)	(1,348)
Investment in securities	0	(481)
Proceeds from sale of available-for-sale securities	1,819	0
Net cash provided by (used in) investing activities	1,247	(1,829)
Financing activities
Proceeds from issuance of common stock	183	30
Cash dividends declared and paid	(2,752)	(2,472)
Repurchase of common stock	(405)	(83)
Cash provided by financing activities	(2,974)	(2,525)
Net change in cash and cash equivalents	(1,972)	3,952
Cash and cash equivalents, beginning of period	10,910	4,669
Cash and cash equivalents, end of period	8,938	8,621
Supplemental disclosure
Cash paid for interest	0	0
Income tax paid	0	3
Non-cash financing activity
Cashless exercise of stock options and related conversion of net shares to stockholders' equity	$ 27	$ 4