STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Operating Activities:
Net income (loss)	$ (1,286,000)	$ 1,534,000
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities
Depreciation and amortization	1,450,000	1,156,000
Changes in allowance for doubtful accounts	62,000	(10,000)
Deferred income tax expense (benefit)	(35,000)	29,000
Stock-based compensation	204,000	353,000
Gain on sale of property and equipment	(80,000)	(30,000)
Changes in operating assets and liabilities:
Accounts receivable	(1,549,000)	(890,000)
Inventories	66,000	132,000
Income tax receivable	(774,000)	286,000
Prepaid expenses and other	117,000	224,000
Accounts payable	(885,000)	(73,000)
Accrued liabilities	(979,000)	291,000
Income tax payable	(264,000)	170,000
Accrued income taxes	26,000	42,000
Tax deficiency from stock-based awards	41,000	12,000
Deferred revenue	(102,000)	(8,000)
Net cash provided by (used in) operating activities	(3,988,000)	3,218,000
Investing Activities:
Purchases of property and equipment	(1,467,000)	(444,000)
Purchases of investments	0	(5,441,000)
Proceeds received from sale or maturity of investments	9,501,000	5,649,000
Proceeds received from sale of property and equipment	5,000	30,000
Net cash provided by (used in) investing activities	8,039,000	(206,000)
Financing Activities:
Proceeds from issuance of common stock, net	46,000	48,000
Tax deficiency from stock-based awards	(41,000)	(12,000)
Repurchase of common stock, net	(312,000)	(1,762,000)
Net cash used in financing activities	(307,000)	(1,726,000)
Increase in cash and cash equivalents	3,744,000	1,286,000
Cash and cash equivalents at beginning of year	8,523,000	7,237,000
Cash and cash equivalents at end of year	12,267,000	8,523,000
Supplemental disclosures for cash flow information:
Cash paid during the year for income taxes	238,000	653,000
Non-cash investing and financing activities:
Purchases of property and equipment included in accounts payable and accrued liabilities	90,000	340,000
Tenant allowance in other assets and deferred rent	0	275,000
Cash dividends declared included in accounts payable	8,233,000	0
Non-cash trade-in value utilized for the purchase of equipment	$ 75,000	$ 0