CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Net cash flows from operating activities:
Net loss	$ 128,000	$ 546,000	$ (505,000)	$ (66,000)
Adjustments to reconcile net loss to net cash from operations:
Depreciation and amortization of property and equipment			3,449,000	3,028,000
Amortization of intangible assets	322,000	322,000	644,000	643,000
Loss on write-down of inventory	0	200,000	115,000	531,000
Current period provision			(150,000)	7,000
Net loss on disposal of property and equipment	162,000	(15,000)	373,000	34,000
Benefit for deferred income taxes			(192,000)	(25,000)
Stock-based compensation			271,000	264,000
Net change in operating assets and liabilities:
Accounts receivable			1,938,000	1,872,000
Inventory			532,000	(293,000)
Other current assets			372,000	98,000
Other non-current assets			14,000	(137,000)
Accounts payable and accrued liabilities			(5,888,000)	(4,374,000)
Customer deposits			(58,000)	193,000
Other non-current liabilities			17,000	0
Net cash provided by operating activities			932,000	1,775,000
Net cash flows from investing activities:
Purchase of investments available for sale			(8,935,000)	(14,637,000)
Redemptions of investments available for sale			6,000,000	7,250,000
Acquisition of property and equipment			(1,965,000)	(3,442,000)
Principal payments received on notes receivable			43,000	0
Proceeds from disposals of property and equipment			41,000	21,000
Net cash used in investing activities			(4,816,000)	(10,808,000)
Net cash flows from financing activities:
Principal payments on long-term debt			(570,000)	(570,000)
Repurchase of common stock			(1,461,000)	(598,000)
Net cash used in financing activities			(2,031,000)	(1,168,000)
Net decrease in cash and cash equivalents			(5,915,000)	(10,201,000)
Cash and cash equivalents - beginning of period			22,777,000	25,705,000	$ 25,705,000
Cash and cash equivalents - end of period	$ 16,862,000	$ 15,504,000	16,862,000	15,504,000	$ 22,777,000
Cash paid during the period for:
Interest, net of capitalized interest			477,000	505,000
Income tax payments, net			9,000	7,000
Non-cash investing and financing activity:
Unrealized holding gains on investments, net of tax			7,000	73,000
Acquisition of property and equipment invoiced or accrued but not yet paid			$ 1,046,000	$ 790,000