Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Cash Flows From Operating Activities:
Net income	$ 1,671,000	$ 6,220,000	$ 5,390,000	$ 11,561,000
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Stock-based compensation			169,000	183,000
Depreciation and amortization	203,000	178,000	401,000	360,000
Loss on marketable equity securities	0	(41,000)	0	18,000
Equity in income of unconsolidated affiliate	(188,000)	(119,000)	(510,000)	(206,000)
Operating lease expense, net of accretion			441,000	450,000
Changes in operating assets and liabilities:
Accounts receivable, net			2,053,000	(3,093,000)
Accounts receivable, related party			(92,000)	(228,000)
Inventories			(5,248,000)	(677,000)
Prepaid expenses			(2,135,000)	(523,000)
Accounts payable and accrued liabilities			(2,894,000)	2,872,000
Customer advance payments of orders			(106,000)	6,475,000
Lease liabilities			(438,000)	(443,000)
Net cash provided by (used in) operating activities			(2,969,000)	16,749,000
Cash Flows From Investing Activities:
Purchases of property and equipment			(1,468,000)	(419,000)
Proceeds from sales of marketable securities			0	47,000
Net cash used in investing activities			(1,468,000)	(372,000)
Cash Flows From Financing Activities:
Proceeds from exercise of stock options			391,000	1,935,000
Repurchase of common stock			(3,708,000)	(125,000)
Net cash provided by (used in) financing activities			(3,317,000)	1,810,000
Increase (decrease) in cash			(7,754,000)	18,187,000
Cash, beginning of the period			23,292,000	6,548,000
Cash, end of the period	$ 15,538,000	$ 24,735,000	$ 15,538,000	$ 24,735,000