Note J - Fair Value of Financial Instruments - Financial Instruments Measured at Fair Value on a Recurring Basis (Details) - Fair Value, Recurring [Member] - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Cash and cash equivalents	$ 59,977	$ 55,646
Restricted cash	7,051	2,358
Total assets	67,028	58,004
Bank Acceptances Executed and Outstanding	6,310	4,628
Convertible senior notes	77,191
Total liabilities	83,501	4,628
Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	59,977	55,646
Restricted cash	7,051	2,358
Total assets	67,028	58,004
Bank Acceptances Executed and Outstanding	0	0
Convertible senior notes	0
Total liabilities	0	0
Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents	0	0
Restricted cash	0	0
Total assets	0	0
Bank Acceptances Executed and Outstanding	6,310	4,628
Convertible senior notes	77,191
Total liabilities	83,501	4,628
Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents	0	0
Restricted cash	0	0
Total assets	0	0
Bank Acceptances Executed and Outstanding	0	0
Convertible senior notes	0
Total liabilities	$ 0	$ 0