Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
OPERATING ACTIVITIES:
Net income	$ 430,000	$ 1,256,000
Adjustments to reconcile net income to net cash provided by (used for) operating activities:
Depreciation and amortization	1,025,000	1,695,000
Stock-based compensation expense	160,000	0
Provision for deferred income taxes	(84,000)	(61,000)
Non-cash interest income	37,000	(37,000)
Equity in loss of affiliate company	239,000	295,000
Increase (Decrease) in Operating Capital [Abstract]
Accounts receivable, net	(653,000)	(792,000)
Other current assets	(185,000)	259,000
Other long-term assets	(41,000)	(45,000)
Accounts payable	567,000	(503,000)
Accrued payroll	(616,000)	(365,000)
Deferred revenue, current portion	(675,000)	651,000
Accrued expenses	196,000	301,000
Other current liabilities	305,000	279,000
Deferred revenue, net of current portion	(79,000)	(59,000)
Net cash provided by operating activities	552,000	2,948,000
Net Cash Provided by (Used in) Investing Activities [Abstract]
Purchase of marketable securities	362,000	440,000
Maturities of marketable securities	324,000	411,000
Purchases of property and equipment	(1,593,000)	(1,628,000)
Advances on notes receivable	(200,000)	0
Proceeds from payments on notes receivable	50,000	55,000
Net cash used for investing activities	(1,781,000)	(1,602,000)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Repurchases of common stock	(1,631,000)	0
Net cash used for financing activities	(1,631,000)	0
Effects of exchange rate changes on cash	(2,000)	(53,000)
Net (decrease) increase in cash	(2,862,000)	1,293,000
Cash at beginning of period	26,918,000	20,399,000
Cash at end of period	24,056,000	21,692,000
Supplemental Cash Flow Information [Abstract]
Purchases of property and equipment, accrued but not paid	$ 262,000	$ 309,000