Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Cash Flows From Operating Activities:
Net income	$ 1,041,000	$ 2,742,000
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Share-based compensation	24,000	33,000
Depreciation and amortization	703,000	721,000
Equity in income of unconsolidated affiliate	$ (32,000)	(300,000)
Gain on investment in common stock warrants		(30,000)
Gain on sale of marketable securities		(379,000)
Deferred income taxes	$ (48,000)	267,000
Changes in assets and liabilities:
Accounts receivable, net	2,571,000	(518,000)
Accounts receivable, related party	325,000	(77,000)
Inventories	146,000	(2,404,000)
Prepaid expenses	1,380,000	(1,504,000)
Accounts payable and accrued liabilities	(139,000)	570,000
Net cash provided by (used in) operating activities	5,971,000	(879,000)
Cash Flows From Investing Activities:
Purchase of property and equipment	(274,000)	(947,000)
Purchase of investments	(175,000)	(134,000)
Proceeds from sale of investments	0	440,000
Net cash used in investing activities	(449,000)	(641,000)
Cash Flows From Financing Activities:
Proceeds from exercise of stock options	765,000	775,000
Repurchase of common stock	(2,110,000)	(2,206,000)
Excess tax benefit from stock options exercised	9,000	231,000
Net cash used in financing activities	(1,336,000)	(1,200,000)
Increase (decrease) in cash	4,186,000	(2,720,000)
Cash, beginning of the year	5,495,000	8,215,000
Cash, end of the year	9,681,000	5,495,000
Supplemental disclosure of cash flow information:
Cash paid for income taxes	$ 303,000	$ 968,000