Note A - Description of Business and Basis of Presentation (Details Textual) - USD ($)				3 Months Ended	23 Months Ended
	Feb. 28, 2019	Oct. 10, 2018	Oct. 05, 2018	Mar. 31, 2019	Sep. 04, 2018	Dec. 31, 2018
Sale of Securities, Value, Available to Issue						$ 150,000,000
Sale of Securities Covered Under Prospectus Supplement, Value, Anticipated Amount to Be Sold Under Registration Statement						18,500,000
Sale of Securities Covered Under Prospectus Supplement, Value, Anticipated Sales Under Purchase Agreement						$ 15,300,000
Sale of Securities Covered Under Prospectus Supplement, Value, Anticipated Sales Under ATM Agreement				$ 3,200,000
Cowen and Company, LLC [Member]
Stock Issued During Period, Shares, New Issues					762,338
Proceeds from Issuance of Common Stock					$ 4,900,000
Sale of Stock, Commission Fee					3.00%
RBC Capital Markets, LLC [Member]
Sale of Stock, Authorized Offering Price					$ 50,000,000
Lincoln Park [Member]
Sale of Securities, Value, Available to Issue	$ 15,000,000
Stock Issued During Period, Shares, New Issues				1,401,271,000,000
Proceeds from Issuance of Common Stock				$ 2,700,000
Purchase Agreement, Term	3 years
Purchase Agreement, Additional Shares to Be Issued as Commitment Shares	120,200
First ATM Agreement [Member]
Stock Issued During Period, Shares, New Issues				1,401,271,000,000
Proceeds from Issuance of Common Stock				$ 2,700,000
Second ATM Agreement [Member]
Stock Issued During Period, Shares, New Issues				0
Second ATM Agreement [Member] | RBC Capital Markets, LLC [Member]
Sale of Stock, Commission Fee					3.00%
Second ATM Agreement [Member] | RBC Capital Markets, LLC [Member] | Maximum [Member]
Sale of Stock, Authorized Offering Price					$ 50,000,000
Underwriting Agreement [Member] | RBC Capital Markets, LLC [Member]
Stock Issued During Period, Shares, New Issues		8,333,334	8,333,334
Shares Issued, Price Per Share		$ 3
Proceeds from Issuance of Common Stock, Net		$ 23,100,000