Note L - Stock-based Compensation - Schedule of Stock Option Activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Outstanding, number of options (in shares)	3,704,755
Outstanding, weighted average exercise price (in dollars per share)	$ 9.35
Outstanding, weighted average remaining contractual term (Year)	7 years 229 days	7 years 175 days
Outstanding, aggregate intrinsic value
Granted, number of options (in shares)	2,291,820
Granted, weighted average exercise price (in dollars per share)	$ 1.84
Exercised or released, number of options (in shares)	(101,739)	(23,682)
Exercised or released, weighted average exercise price (in dollars per share)
Canceled or forfeited, number of options (in shares)	(675,950)
Canceled or forfeited, weighted average exercise price (in dollars per share)	$ 8.80
Expired, number of options (in shares)	(26,664)
Expired, weighted average exercise price (in dollars per share)	$ 4.80
Outstanding, number of options (in shares)	5,192,222	3,704,755
Outstanding, weighted average exercise price (in dollars per share)	$ 6.31	$ 9.35
Exercisable, number of options (in shares)	2,154,640
Exercisable, weighted average exercise price (in dollars per share)	$ 10.80
Exercisable, weighted average remaining contractual term (Year)	6 years 14 days
Vested and expected to vest, number of options (in shares)	4,503,063
Vested and expected to vest, weighted average exercise price (in dollars per share)	$ 7.16
Vested and expected to vest, weighted average remaining contractual term (Year)	7 years 109 days