Note F - Earnings Per Share - Computation of Basic and Diluted Net Income (Loss) per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net loss	$ (13,439)	$ (9,616)	$ (18,600)	$ (16,797)	$ (35,430)	$ (8,780)	$ (11,366)	$ (10,474)	$ (58,452)	$ (66,049)	$ (2,146)
Basic (in shares)									21,866,630	19,982,363	19,646,646
Effect of dilutive options and restricted stock units (in shares)									0	0	0
Diluted (in shares)									21,866,630	19,982,363	19,646,646
Basic (in dollars per share)	$ (0.57)	$ (0.42)	$ (0.89)	$ (0.83)	$ (1.76)	$ (0.44)	$ (0.57)	$ (0.53)	$ (2.67)	$ (3.31)	$ (0.11)
Diluted (in dollars per share)	$ (0.57)	$ (0.42)	$ (0.89)	$ (0.83)	$ (1.76)	$ (0.44)	$ (0.57)	$ (0.53)	$ (2.67)	$ (3.31)	$ (0.11)