Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating activities
Net income	$ 503	$ 50
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Inventories allowances	(31)	49
Deferred taxes	178	100
Depreciation and amortization	439	471
Share-based and stock compensation expense	38	16
Restricted stock unit compensation expense	73	6
Loss (gain) on investment in securities	1,201	(617)
Loss on disposal of property, plant and equipment	0	104
Changes in operating assets and liabilities:
Trade accounts receivable	(1,459)	(1,865)
Inventories	1,608	(843)
Prepaid expenses and other current assets	(99)	527
Other assets	23	(25)
Accounts payable	(2,437)	899
Accrued compensation and related taxes	251	(838)
Accrued warranty expense	26	410
Deferred revenue	582	(6)
Accrued other expenses and other current liabilities	(185)	203
Net cash provided by (used in) operating activities	711	(1,359)
Investing activities
Purchases of property, plant and equipment	(569)	(447)
Investment in securities	(3,741)	0
Proceeds from sale of available-for-sale securities	8,335	897
Net cash provided by investing activities	4,025	450
Financing activities
Proceeds from issuance of common stock	0	183
Cash dividends declared and paid	(544)	(2,477)
Repurchase of common stock	(616)	(217)
Net cash used in financing activities	(1,160)	(2,511)
Net change in cash and cash equivalents	3,576	(3,420)
Cash and cash equivalents, beginning of period	7,147	10,910
Cash and cash equivalents, end of period	10,723	7,490
Supplemental disclosure
Cash paid for interest	0	0
Income tax paid	0	0
Non-cash financing activity
Restricted stock units issued	140	0
Cashless exercise of stock options and related conversion of net shares to stockholders' equity	$ 0	$ 27