Note F - Common Stock and Warrants (Details Textual) - USD ($) $ / shares in Units, $ in Millions			12 Months Ended
	Oct. 25, 2018	Jun. 02, 2014	Dec. 31, 2013	Mar. 31, 2020	Dec. 31, 2019
Common Stock, Shares Authorized (in shares)				250,000,000	250,000,000
Common Stock, Shares, Issued, Total (in shares)				56,760,111	36,350,785
Common Stock, Shares, Outstanding, Ending Balance (in shares)				56,760,111	36,350,785
Common Stock [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)			143,466
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)			$ 5.85
2013 Warrants [Member]
Debt Instrument, Face Amount			$ 3.8
Class of Warrant or Right Issued (in shares)			1,079,453
Series D Redeemable Convertible Preferred Stock [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)			1,079,453
Deerfield Warrant [Member]
Class of Warrant or Right Issued (in shares)		14,423,076
Deerfield Warrant [Member] | Common Stock [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)		1,923,077
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 5.85
Warrant Issued to KVK [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	500,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 2.30
Class of Warrant or Right, Additional Shares Exercisable for Each Milestones (in shares)	125,000