Consolidated Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
OPERATING ACTIVITIES:
Net (loss) income	$ 2,909,000	$ 12,885,000
us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract
Depreciation and amortization	5,011,000	3,636,000
Stock-based compensation expense	150,000	160,000
Deferred income taxes	69,000	312,000
Non-cash investment loss (income)	1,000,000	(18,000)
Equity in loss (gain) of affiliate company	701,000	(195,000)
Changes in operating assets and liabilities:
Accounts receivable, net	7,345,000	(2,268,000)
Other current assets	(2,329,000)	(2,620,000)
Other long-term assets	563,000	(41,000)
Accounts payable	(78,000)	600,000
Accrued payroll	53,000	336,000
Deferred revenue, current portion	2,649,000	(1,134,000)
Accrued expenses	281,000	(54,000)
Other current liabilities	40,000	(1,052,000)
Deferred revenue, net of current portion	(112,000)	310,000
Net cash provided by operating activities	18,252,000	10,857,000
INVESTING ACTIVITIES:
Purchases of property and equipment	(4,845,000)	(7,532,000)
Advances on notes and interest receivable	450,000
Proceeds from payments on notes receivable	147,000	165,000
Purchase of marketable securities	(1,776,000)	(988,000)
Maturities of marketable securities	1,602,000
Purchase of long-term investment	(155,000)
Net cash used for investing activities	(5,477,000)	(8,355,000)
FINANCING ACTIVITIES:
Repurchases of common stock	(1,528,000)	(5,042,000)
Net cash used for financing activities	(1,528,000)	(5,042,000)
Effects of exchange rate changes on cash	(32,000)	364,000
Net increase (decrease) in cash	11,215,000	(2,176,000)
Cash at beginning of period	20,399,000	29,244,000
Cash at end of period	31,614,000	27,068,000
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid during the period for income taxes	$ 168,000	5,330,000
Purchases of property and equipment, accrued but not paid		$ 207,000