Condensed Consolidated Statements Of Cash Flows (USD $)	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ (212,000)	$ 3,810,000
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	1,368,000	1,586,000
Provision for doubtful accounts	(95,000)	(72,000)
Deferred taxes		457,000
Foreign currency transaction (gains) losses	(19,000)	(68,000)
Realized gains on available for sale securities	(6,000)
Stock compensation costs	349,000	343,000
Changes in operating assets and liabilities:
Accounts receivable	2,943,000	(2,365,000)
Inventories	(1,435,000)	1,928,000
Income tax refunds receivable	(185,000)	214,000
Other assets	(79,000)	4,000
Accounts payable	95,000	(1,149,000)
Advance customer payments	(224,000)	(168,000)
Accrued expenses	(810,000)	536,000
Net cash provided by operating activities	1,690,000	5,056,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from maturities of available-for-sale marketable securities	10,584,000	7,571,000
Proceeds from sales of available-for-sale marketable securities	2,936,000	2,800,000
Purchases of available-for-sale marketable securities	(18,681,000)	(12,334,000)
Additions to equipment and leasehold improvements	(1,086,000)	(536,000)
Additions to patents	(95,000)	(66,000)
Net cash used in investing activities	(6,342,000)	(2,565,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercise of stock options		12,000
Proceeds from issuance of common stock under employee stock purchase plan	139,000	201,000
Net cash provided by financing activities	139,000	213,000
Effects of exchange rate changes on cash and cash equivalents	104,000	(85,000)
Net increase (decrease) in cash and cash equivalents	(4,409,000)	2,619,000
Cash and cash equivalents - beginning of period	13,791,000	8,427,000
Cash and cash equivalents - end of period	$ 9,382,000	$ 11,046,000