Note F - Long-term Debt (Details Textual) - USD ($) $ in Thousands						3 Months Ended
	May 11, 2020	Apr. 14, 2020	May 07, 2019	Jan. 09, 2018	Apr. 17, 2017	Jun. 30, 2020	Dec. 31, 2019
Letters of Credit Outstanding, Amount						$ 0
Standby Letters of Credit [Member]
Long-term Line of Credit, Total						1,700
Texas Capital Facility [Member]
Long-term Line of Credit, Total						17,200	$ 18,700
Line of Credit Facility, Remaining Borrowing Capacity						100
Texas Capital Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 19,000			$ 22,000
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage					0.50%
Line of Credit Facility, Collateral Fees, Percentage					0.50%
Line of Credit Facility, Collateral Fees, Amount						100
Debt Instrument, Term, Extension Period (Year)	1 year		1 year	1 year
Texas Capital Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate					1.95%
Texas Capital Credit Facility [Member] | Prime Rate [Member]
Debt Instrument, Basis Spread on Variable Rate					0.75%
Texas Capital Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity					$ 20,000
Texas Capital Credit Facility [Member] | Standby Letters of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity					$ 5,000
Paycheck Protection Program CARES Act [Member]
Proceeds from Notes Payable, Total		$ 10,000
Debt Instrument, Due Within Twelve Months If Not Forgiven						$ 5,000