Note J - Common Stock and Warrants - Reserved Authorized Shares of Common Stock for Future Issuance (Details) - shares	Dec. 31, 2018	Dec. 31, 2017
Common shares reserved for future issuance (in shares)	13,641,913	12,618,711
Series A Convertible Preferred Stock [Member]
Common shares reserved for future issuance (in shares)	1,112,334
Warrant [Member]
Common shares reserved for future issuance (in shares)	2,527,763	2,027,763
Stock Compensation Plan [Member]
Common shares reserved for future issuance (in shares)	3,704,755	2,853,924
Possible Future Issuances Under Equity Incentive Plans [Member]
Common shares reserved for future issuance (in shares)	648,272	944,700
2021 Notes [Member]
Common shares reserved for future issuance (in shares)	4,481,182	5,040,914
Convertible Notes Payable [Member]
Common shares reserved for future issuance (in shares)	1,167,607	1,751,410