Note K - Notes Payable and Long-term Debt - Schedule of Notes Payable and Long-term Debt (Details) (Parentheticals) - USD ($)			12 Months Ended
	Mar. 30, 2018	Sep. 28, 2017	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2019	Mar. 05, 2019
Chailease Finance Co, Ltd. [Member] | Promissory Note [Member]
Long-term debt, maturity date			Nov. 30, 2021	Nov. 30, 2021
Long-term debt, interest			3.40%	3.40%
Chailease Finance Co, Ltd. [Member] | Promissory Note 2 [Member]
Long-term debt, maturity date			Jan. 21, 2022
Long-term debt, interest			3.10%
Branch Banking and Trust Company [Member] | Revolving Credit Facility [Member]
Long-term debt, maximum	$ 60,000,000	$ 50,000,000			$ 20,000,000	$ 25,000,000
Taishin International Bank [Member] | Revolving Credit Facility [Member]
Long-term debt, maturity date				May 31, 2019
Long-term debt, maximum				$ 9,767,000
Long-term debt, interest				2.00%
Development Bank of Singapore (Taiwan) Ltd. [Member] | Revolving Credit Facility [Member]
Long-term debt, maturity date				Jul. 26, 2019
Long-term debt, maximum				$ 7,000,000
Development Bank of Singapore (Taiwan) Ltd. [Member] | Revolving Credit Facility [Member] | Minimum [Member]
Long-term debt, interest				1.50%
Development Bank of Singapore (Taiwan) Ltd. [Member] | Revolving Credit Facility [Member] | Maximum [Member]
Long-term debt, interest				3.50%
Far Eastern [Member] | Revolving Credit Facility [Member]
Long-term debt, maturity date			Apr. 11, 2020
Long-term debt, maximum			$ 2,668,000
Long-term debt, interest			1.70%
SPD Bank [Member] | Revolving Credit Facility [Member]
Long-term debt, maturity date			May 24, 2024
Long-term debt, maximum			$ 25,449,000
Long-term debt, interest			4.57%
China Zheshang Bank Co., Ltd [Member] | Revolving Credit Facility [Member]
Long-term debt, maturity date			Jun. 20, 2022
Long-term debt, maximum			$ 7,167,000
Long-term debt, interest			5.70%
London Interbank Offered Rate (LIBOR) [Member] | Branch Banking and Trust Company [Member] | Revolving Credit Facility [Member]
Long-term debt, interest		1.50%
London Interbank Offered Rate (LIBOR) [Member] | Branch Banking and Trust Company [Member] | Revolving Credit Facility [Member] | Minimum [Member]
Long-term debt, interest	1.40%
London Interbank Offered Rate (LIBOR) [Member] | Branch Banking and Trust Company [Member] | Revolving Credit Facility [Member] | Maximum [Member]
Long-term debt, interest	2.00%
Term Loan [Member] | Branch Banking and Trust Company [Member]
Long-term debt, maturity date				Apr. 01, 2024
Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member] | Branch Banking and Trust Company [Member]
Long-term debt, interest				1.15%
Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member] | Branch Banking and Trust Company [Member] | Minimum [Member]
Long-term debt, interest	1.15%
Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member] | Branch Banking and Trust Company [Member] | Maximum [Member]
Long-term debt, interest	2.00%
CapEx Loan [Member] | Branch Banking and Trust Company [Member]
Long-term debt, maturity date				Apr. 01, 2023
Long-term debt, maturity date				Dec. 18, 2023
CapEx Loan [Member] | London Interbank Offered Rate (LIBOR) [Member] | Branch Banking and Trust Company [Member]
Long-term debt, interest				1.30%
CapEx Loan [Member] | London Interbank Offered Rate (LIBOR) [Member] | Branch Banking and Trust Company [Member] | Minimum [Member]
Long-term debt, interest	1.30%
CapEx Loan [Member] | London Interbank Offered Rate (LIBOR) [Member] | Branch Banking and Trust Company [Member] | Maximum [Member]
Long-term debt, interest	2.00%
Credit Facility [Member] | Taishin International Bank [Member] | Revolving Credit Facility [Member]
Long-term debt, maturity date			Jul. 31, 2020
Long-term debt, maximum			$ 3,336,000
Long-term debt, interest			2.20%