CONDENSED STATEMENTS OF CASH FLOWS - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating Activities:
Net loss	$ (863,000)	$ (1,096,000)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	148,000	335,000
Impairment loss	159,000	0
Changes in allowance for doubtful accounts	9,000	(3,000)
Deferred income tax benefit	0	(214,000)
Stock-based compensation expense	49,000	138,000
Accrued interest on held to maturity investments	0	(13,000)
Changes in operating assets and liabilities:
Accounts receivable	1,351,000	2,406,000
Inventories	9,000	(25,000)
Income tax receivable	(119,000)	2,000
Prepaid expenses and other	4,000	39,000
Accounts payable	(208,000)	(1,263,000)
Accrued liabilities	(501,000)	(1,900,000)
Income tax payable	9,000	8,000
Deferred revenue	210,000	500,000
Net cash provided by (used in) operating activities	257,000	(1,086,000)
Investing Activities:
Purchases of property and equipment	(32,000)	(235,000)
Purchase of investments	0	(4,981,000)
Net cash used in investing activities	(32,000)	(5,216,000)
Financing Activities:
Proceeds from issuance of common stock	20,000	108,000
Net cash provided by financing activities	20,000	108,000
Increase (decrease) in cash and cash equivalents	245,000	(6,194,000)
Cash and cash equivalents at beginning of period	7,510,000	10,160,000
Cash and cash equivalents at end of period	7,755,000	3,966,000
Supplemental disclosures for cash flow information:
Cash paid during the period for income taxes	112,000	0
Non-cash investing and financing activities:
Purchases of property and equipment included in accounts payable	$ 0	$ 35,000