Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash Flows From Operating Activities:
Net income	$ 27,086,000	$ 3,000,000
Adjustments to reconcile net income to net cash provided by operating activities:
Share-based compensation	375,000	451,000
Depreciation and amortization	729,000	602,000
(Gain) Loss on marketable securities	62,000	(231,000)
Equity in income of unconsolidated affiliate	(710,000)	(359,000)
Operating lease expense, net of accretion	(357,000)	704,000
Deferred income taxes	(13,000)	83,000
Changes in assets and liabilities:
Accounts receivable, net	(4,564,000)	1,367,000
Accounts receivable, related party	(181,000)	(341,000)
Inventories	(5,446,000)	(1,425,000)
Prepaid expenses	(2,638,000)	412,000
Accounts payable and accrued liabilities	3,355,000	(500,000)
Customer advance payments of orders	209,000
Lease liabilities	367,000	(662,000)
Net cash provided by operating activities	18,274,000	3,101,000
Cash Flows From Investing Activities:
Purchase of property and equipment	(1,135,000)	(1,296,000)
Proceeds from sales of marketable securities	273,000	154,000
Net cash used in investing activities	(862,000)	(1,142,000)
Cash Flows From Financing Activities:
Proceeds from exercise of stock options	1,998,000	130,000
Repurchase of common stock	(2,666,000)	(2,548,000)
Net cash used in financing activities	(668,000)	(2,418,000)
Increase (decrease) in cash and cash equivalents	16,744,000	(459,000)
Cash and cash equivalents, beginning of the year	6,548,000	7,007,000
Cash and cash equivalents, end of the year	23,292,000	6,548,000
Supplemental disclosure of cash flow information:
Cash paid for income taxes	$ 4,136,000	$ 633,000