Note E - Marketable Securities and Time Deposits - Marketable Debt Securities by Contractual Maturities (Details) $ in Thousands	Sep. 30, 2021 USD ($)
Marketable debt securities, amortized cost	$ 87,754
Marketable debt securities, unrealized gains	230
Marketable debt securities, unrealized losses	(350)
Marketable debt securities, estimated fair value	86,634
Due in One Year or Less [Member]
Marketable debt securities, amortized cost	27,228
Marketable debt securities, unrealized gains	21
Marketable debt securities, unrealized losses	(50)
Marketable debt securities, estimated fair value	27,200
Due after One Year to Five Years [Member]
Marketable debt securities, amortized cost	59,526
Marketable debt securities, unrealized gains	209
Marketable debt securities, unrealized losses	(300)
Marketable debt securities, estimated fair value	$ 59,434

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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