Note J - Stock Option Plans - Summary of Option Activity for Employees and Non-employees (Details) - Share-based Payment Arrangement, Option [Member] - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Number of options granted (in shares)	592,358	592,358
Share-based Payment Arrangement, Employee [Member]
Number of options (in shares)	1,212,442	1,670,221
Weighted average exercise price, outstanding (in dollars per share)	$ 1.61	$ 1.71
Weighted average remaining contractual life, outstanding (Year)	3 years 32 days	2 years	2 years 146 days
Aggregate intrinsic value, outstanding	$ 476,964
Number of options granted (in shares)	1,135,277
Weighted average exercise price, granted (in dollars per share)	$ 2
Weighted average remaining contractual life, granted (Year)	4 years 299 days
Aggregate intrinsic value, granted	$ 137,186
Number of options exercised (in shares)	(336,970)
Weighted average exercise price, exercised (in dollars per share)	$ 1.14
Weighted average remaining contractual life, exercised (Year)
Aggregate intrinsic value, exercised
Number of options forfeited and expired (in shares)	(57,306)	(457,779)
Weighted average exercise price, forfeited or expired (in dollars per share)	$ 3.89	$ 1.96
Number of options (in shares)	1,953,443	1,212,442	1,670,221
Weighted average exercise price, outstanding (in dollars per share)	$ 1.88	$ 1.61	$ 1.71
Number of options exercisable (in shares)	1,169,925
Weighted average exercise price, exercisable (in dollars per share)	$ 1.79
Weighted average remaining contractual life, exercisable (Year)	1 year 328 days
Aggregate intrinsic value, exercisable	$ 385,507
Number of options exercised (in shares)	336,970
Share-based Payment Arrangement, Nonemployee [Member]
Number of options (in shares)	49,998	33,332
Weighted average exercise price, outstanding (in dollars per share)	$ 1.87	$ 1.87
Weighted average remaining contractual life, outstanding (Year)	3 years 65 days	2 years 343 days	2 years 343 days
Aggregate intrinsic value, outstanding	$ 54,748
Number of options granted (in shares)	33,332	16,666
Weighted average exercise price, granted (in dollars per share)	$ 1.71	$ 0.55
Weighted average remaining contractual life, granted (Year)	4 years 219 days	4 years 156 days
Aggregate intrinsic value, granted	$ 13,666	$ 13,999
Number of options exercised (in shares)
Weighted average exercise price, exercised (in dollars per share)
Number of options forfeited and expired (in shares)	(8,333)
Weighted average exercise price, forfeited or expired (in dollars per share)	$ 2.70
Number of options (in shares)	74,997	49,998	33,332
Weighted average exercise price, outstanding (in dollars per share)	$ 1.41	$ 1.87	$ 1.87
Number of options exercisable (in shares)	47,220
Weighted average exercise price, exercisable (in dollars per share)	$ 1.38
Weighted average remaining contractual life, exercisable (Year)	2 years 200 days
Aggregate intrinsic value, exercisable	$ 36,915
Number of options exercised (in shares)