Note L - Convertible Senior Notes - Schedule of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Amortization of debt issuance costs			$ 892	$ 42	$ 81
The 5% Convertible Senior Notes Due 2024 [Member]
Contractual interest expense	$ 984	$ 0	3,276	0
Amortization of debt issuance costs	207	0	681	0
Total interest cost	$ 1,191	$ 0	$ 3,957	$ 0
Effective interest rate	5.10%	0.00%	5.10%	0.00%