Note O - Accumulated Other Comprehensive Income (Loss) - Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Gains on available-for-sale marketable securities		$ 400	$ 403	$ 713	$ 799
Provision for income taxes		(383)	(2)	(612)	(211)
Net income		(521)	(288)	(1,587)	(2,041)
Research and development	[1]	8,559	8,891	17,481	17,889
Sales and marketing	[2]	4,386	3,761	8,869	7,829
General and administrative	[3]	2,674	2,669	5,229	5,250
Net income		(904)	$ (290)	(2,199)	$ (2,252)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Gains on available-for-sale marketable securities		(3)
Net income		(22)		(54)
Reclassification out of Accumulated Other Comprehensive Income [Member] | AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Gains on available-for-sale marketable securities				43
Provision for income taxes
Net income		(3)		43
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Provision for income taxes
Net income		(23)		(105)
Research and development		(18)		(83)
Sales and marketing		(2)		(8)
General and administrative		(3)		(14)
Net income		(23)		(105)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Provision for income taxes
Net income		4		8
Research and development		3		6
Sales and marketing		1		2
General and administrative		$ 4		$ 8

[1] Includes equity-based compensation expense in the amount of $775 and $701 for the three months ended June 30, 2019 and 2018, respectively; and $1,525 and $1,353 for the six months ended June 30, 2019 and 2018, respectively.

[2] Includes equity-based compensation expense in the amount of $474 and $265 for the three months ended June 30, 2019 and 2018, respectively; and $876 and $671 for the six months ended June 30, 2019 and 2018, respectively.

[3] Includes equity-based compensation expense in the amount of $689 and $586 for the three months ended June 30, 2019 and 2018, respectively; and $1,327 and $1,129 for the six months ended June 30, 2019 and 2018, respectively.