Note M - Accrued Liabilities - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued payroll	$ 11,009	$ 10,772
Accrued rent	0	1,200
Accrued employee benefits	2,288	2,862
Accrued state and local taxes	1,215	1,088
Accrued interest	1,208	163
Advance payments	312	426
Accrued product warranty	821	995
Accrued commission expenses	420	398
Accrued professional fees	222	315
Accrued capital expenditures	0	371
Accrued other	369	701
Total accrued liabilities	$ 17,864	$ 19,291