STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Operating Activities:
Net income (loss)	$ (639,000)	$ (1,286,000)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities
Depreciation and amortization	1,348,000	1,450,000
Changes in allowance for doubtful accounts	72,000	62,000
Deferred income tax expense (benefit)	40,000	(35,000)
Stock-based compensation	387,000	204,000
Gain on sale of property and equipment	0	(80,000)
Changes in operating assets and liabilities:
Accounts receivable	(2,057,000)	(1,549,000)
Inventories	24,000	66,000
Income tax receivable	415,000	(774,000)
Prepaid expenses and other	274,000	117,000
Accounts payable	697,000	(885,000)
Accrued liabilities	882,000	(979,000)
Income tax payable	0	(264,000)
Accrued income taxes	27,000	26,000
Tax deficiency from stock-based awards	0	41,000
Deferred revenue	310,000	(102,000)
Net cash provided by (used in) operating activities	1,780,000	(3,988,000)
Investing Activities:
Purchases of property and equipment	(1,159,000)	(1,467,000)
Proceeds received from sale or maturity of investments	0	9,501,000
Proceeds received from sale of property and equipment	0	5,000
Net cash provided by (used in) investing activities	(1,159,000)	8,039,000
Financing Activities:
Cash dividends paid ($0.70 per share)	(8,177,000)	0
Proceeds from issuance of common stock, net	0	46,000
Repurchase of common stock upon vesting of restricted stock awards	(16,000)	0
Tax deficiency from stock-based awards	0	(41,000)
Repurchase of common stock, net	0	(312,000)
Net cash used in financing activities	(8,193,000)	(307,000)
Increase (decrease) in cash and cash equivalents	(7,572,000)	3,744,000
Cash and cash equivalents at beginning of year	12,267,000	8,523,000
Cash and cash equivalents at end of year	4,695,000	12,267,000
Supplemental disclosures for cash flow information:
Cash (refunded) paid during the year for income taxes	(743,000)	238,000
Non-cash investing and financing activities:
Cash dividends declared included in accounts payable	56,000	8,233,000
Purchases of property and equipment included in accounts payable and accrued liabilities	39,000	90,000
Non-cash trade-in value utilized for the purchase of equipment	$ 0	$ 75,000