Consolidated Balance Sheets - USD ($)	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 16,290,000				$ 16,307,000
Accounts receivable, net of allowance for doubtful accounts of $45,000 as of December 31, 2022 and $64,000 as of December 31, 2021	5,382,000				3,397,000
Accounts receivable, related party	1,591,000				1,383,000
Inventories	24,397,000				24,969,000
Prepaid expenses	4,902,000				6,943,000
Total current assets	52,562,000				52,999,000
Property and equipment, net	5,742,000				6,064,000
Goodwill	55,000				55,000
Definite-lived intangible assets, net	1,000				3,000
Right-of-use assets	1,725,000				2,648,000
Equity investment in unconsolidated affiliate	4,718,000	$ 4,783,000	$ 4,932,000	$ 5,147,000,000	5,251,000	$ 5,183,000	$ 5,257,000	$ 4,990,000,000
Total assets	64,803,000	65,081,000	66,694,000	66,747,000,000	67,020,000	67,025,000	66,804,000	67,573,000,000
Current liabilities:
Accounts payable	674,000				528,000
Accrued liabilities	833,000				1,250,000
Lease liabilities	899,000				883,000
Total current liabilities	2,406,000				2,661,000
Lease liabilities, net of current portion	875,000				1,817,000
Deferred income tax liabilities, net	764,000				791,000
Total liabilities	4,045,000				5,269,000
Commitments and Contingencies
Shareholders' equity:
Common stock, $.01 par value: 50,000,000 shares authorized; 12,226,306 and 13,115,341 shares outstanding as of December 31, 2022 and December 31, 2021, respectively	123,000				132,000
Retained earnings	62,124,000	62,559,000	63,108,000	63,311,000,000	62,488,000	62,596,000	62,130,000	61,648,000,000
Accumulated other comprehensive loss	(1,489,000)	(1,424,000)	(1,287,000)	(1,022,000,000)	(869,000)	(989,000)	(802,000)	(881,000,000)
Total shareholders' equity	60,758,000	61,261,000	61,949,000	62,419,000,000	61,751,000	61,739,000	61,460,000	60,901,000,000	$ 58,757,000
Total liabilities and shareholders' equity	$ 64,803,000	$ 65,081,000	$ 66,694,000	$ 66,747,000,000	$ 67,020,000	$ 67,025,000	$ 66,804,000	$ 67,573,000,000