CONDENSED STATEMENTS OF CASH FLOWS - USD ($)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating Activities:
Net income (loss)	$ (1,584,000)	$ 348,000
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	742,000	570,000
Changes in allowance for doubtful accounts	(2,000)	(36,000)
Deferred income tax benefit	(388,000)	0
Stock-based compensation expense	277,000	149,000
Accrued interest on held to maturity investments	(33,000)	0
Changes in operating assets and liabilities:
Accounts receivable	2,517,000	2,296,000
Inventories	(8,000)	(63,000)
Income tax receivable	(3,000)	107,000
Prepaid expenses and other	92,000	109,000
Accounts payable	(459,000)	(131,000)
Accrued liabilities	(1,924,000)	17,000
Accrued income taxes	15,000	15,000
Deferred revenue	134,000	659,000
Net cash provided by (used in) operating activities	(624,000)	4,040,000
Investing Activities:
Purchases of property and equipment	(358,000)	(528,000)
Purchase of investments	(4,981,000)	0
Net cash used in investing activities	(5,339,000)	(528,000)
Financing Activities:
Proceeds from issuance of common stock	108,000	49,000
Repurchase of common stock upon vesting of restricted stock awards	(9,000)	(14,000)
Cash dividends paid ($0.70 per share)	(14,000)	(14,000)
Repurchase of common stock, net	0	(187,000)
Net cash provided by (used in) financing activities	85,000	(166,000)
Increase (decrease) in cash and cash equivalents	(5,878,000)	3,346,000
Cash and cash equivalents at beginning of period	10,160,000	4,695,000
Cash and cash equivalents at end of period	4,282,000	8,041,000
Supplemental disclosures for cash flow information:
Cash paid during the period for income taxes	6,000	0
Non-cash investing and financing activities:
Purchases of property and equipment included in accounts payable	$ 0	$ 111,000