CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 4,276,000	$ 606,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,899,000	2,102,000
Non-cash operating lease expense	384,000	0
Provision (recovery) for doubtful accounts	43,000	(31,000)
Deferred taxes	289,000	107,000
Foreign currency transaction gains	(181,000)	(112,000)
Share-based compensation	863,000	737,000
Unrealized loss on available-for-sale equity security	23,000	10,000
Changes in operating assets and liabilities:
Accounts and trade notes receivable	(1,721,000)	2,568,000
Inventories	(6,380,000)	(1,123,000)
Prepaid expenses and other assets	(785,000)	235,000
Accounts payable	3,060,000	(3,538,000)
Advance customer payments and other	208,000	(50,000)
Accrued expenses	1,120,000	(1,077,000)
Operating leases	(616,000)	482,000
Net cash provided by operating activities	2,482,000	916,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from maturities of available-for-sale marketable securities	9,016,000	6,144,000
Purchases of available-for-sale marketable securities	(10,637,000)	(7,080,000)
Additions to equipment and leasehold improvements	(1,049,000)	(1,065,000)
Additions to patents	(115,000)	(88,000)
Net cash used in investing activities	(2,785,000)	(2,089,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercise of stock options	322,000	173,000
Tax payments for shares withheld related to stock option exercises	(420,000)	0
Common stock repurchases	0	(353,000)
Proceeds from issuance of common stock under employee stock purchase plan	224,000	203,000
Net cash provided by financing activities	126,000	23,000
Effects of exchange rate changes on cash and cash equivalents	6,000	6,000
Net decrease in cash and cash equivalents	(171,000)	(1,144,000)
Cash and cash equivalents – beginning of period	5,836,000	9,248,000
Cash and cash equivalents – end of period	$ 5,665,000	$ 8,104,000