Note A - Basis of Presentation and Summary of Significant Accounting Policies - Impact of New Standard on Consolidated Balance Sheet and Consolidated Statements of Operations (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Income statement
Revenues		$ 30,651	$ 31,301	$ 58,762	$ 59,234
Cost of revenues	[1]	15,598	16,804	29,995	32,490
Gross margin:		15,053	14,497	28,767	26,744
Research and development, net	[2]	8,891	9,161	17,889	18,351
Sales and marketing	[3]	3,761	3,430	7,829	7,005
General and administrative	[4]	2,669	2,372	5,250	4,859
Amortization of intangible assets		425	425	850	850
Total operating expenses:		15,746	15,388	31,818	31,065
Operating loss:		(693)	(891)	(3,051)	(4,321)
Financial income, net		403	418	799	834
Loss before taxes on income		(290)	(473)	(2,252)	(3,487)
Taxes on income		(2)	113	(211)	(35)
Net Loss		(288)	$ (586)	(2,041)	$ (3,452)
Assets
Trade receivables		16,622		16,622		$ 13,416
Inventories		8,366		8,366		9,422
Other accounts receivable and prepaid expenses		3,196		3,196		3,167
Liabilities
Accrued expenses and other accounts payable		(2,746)		(2,746)		(2,888)
Equity
Accumulated deficit		(110,420)		(110,420)		$ (104,842)
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Income statement
Revenues		30,625		57,782
Cost of revenues		15,602		29,619
Gross margin:		15,023		28,163
Research and development, net		8,891		17,889
Sales and marketing		3,763		7,778
General and administrative		2,669		5,250
Amortization of intangible assets		425		850
Total operating expenses:		15,748		31,767
Operating loss:		(725)		(3,604)
Financial income, net		403		799
Loss before taxes on income		(322)		(2,805)
Taxes on income		(2)		(211)
Net Loss		(320)		(2,594)
Assets
Trade receivables		15,526		15,526
Inventories		8,760		8,760
Other accounts receivable and prepaid expenses		3,251		3,251
Liabilities
Accrued expenses and other accounts payable		(2,746)		(2,746)
Equity
Accumulated deficit		(111,067)		(111,067)
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Income statement
Revenues		26		980
Cost of revenues		(4)		376
Gross margin:		30		604
Research and development, net
Sales and marketing		(2)		51
General and administrative
Amortization of intangible assets
Total operating expenses:		(2)		51
Operating loss:		32		553
Financial income, net
Loss before taxes on income		32		553
Taxes on income
Net Loss		32		553
Assets
Trade receivables		1,096		1,096
Inventories		(394)		(394)
Other accounts receivable and prepaid expenses		(55)		(55)
Liabilities
Accrued expenses and other accounts payable
Equity
Accumulated deficit		$ 647		$ 647

[1] Includes equity-based compensation expense in the amount of $108 and $94 for the three months ended June 30, 2018 and 2017, and $206 and $191 for the six months ended June 30, 2018 and 2017, respectively.

[2] Includes equity-based compensation expense in the amount of $701 and $623 for the three months ended June 30, 2018 and 2017, respectively; and $1,353 and $1,239 for the six months ended June 30, 2018 and 2017, respectively.

[3] Includes equity-based compensation expense in the amount of $265 and $297 for the three months ended June 30, 2018 and 2017, respectively; and $671 and $597 for the six months ended June 30, 2018 and 2017, respectively.

[4] Includes equity-based compensation expense in the amount of $586 and $543 for the three months ended June 30, 2018 and 2017, respectively; and $1,129 and $1,061 for the six months ended June 30, 2018 and 2017, respectively.