Note G - Stock-based Compensation - Summarizes Information About Stock Option (Details)	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Weighted-average exercise price, outstanding (in dollars per share)	$ 40.25
Weighted-average remaining life (Year)	5 years 167 days
Exercise price range, number exercisable (in shares) | shares	80,336
Weighted-average exercise price, exercisable (in dollars per share)	$ 43.28
Exercise Price Range One [Member]
Exercise price range, lower limit (in dollars per share)	1.57
Exercise price range, higher limit (in dollars per share)	$ 7.40
Exercise price range, number outstanding (in shares) | shares	46,727
Weighted-average exercise price, outstanding (in dollars per share)	$ 3.42
Weighted-average remaining life (Year)	8 years 116 days
Exercise price range, number exercisable (in shares) | shares	39,316
Weighted-average exercise price, exercisable (in dollars per share)	$ 2.67
Exercise Price Range Two [Member]
Exercise price range, lower limit (in dollars per share)	76.80
Exercise price range, higher limit (in dollars per share)	$ 115.20
Exercise price range, number outstanding (in shares) | shares	39,320
Weighted-average exercise price, outstanding (in dollars per share)	$ 80.43
Weighted-average remaining life (Year)	2 years 109 days
Exercise price range, number exercisable (in shares) | shares	39,320
Weighted-average exercise price, exercisable (in dollars per share)	$ 80.43
Exercise Price Range Three [Member]
Exercise price range, lower limit (in dollars per share)	123.10
Exercise price range, higher limit (in dollars per share)	$ 184.65
Exercise price range, number outstanding (in shares) | shares	1,700
Weighted-average exercise price, outstanding (in dollars per share)	$ 123.10
Weighted-average remaining life (Year)	36 days
Exercise price range, number exercisable (in shares) | shares	1,700
Weighted-average exercise price, exercisable (in dollars per share)	$ 123.10