Note I - Net Loss Per Share - Anti-dilutive Securities (Details) - shares		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Antidilutive securities (in shares)		30,451,374	14,405,932
Convertible Debt Securities [Member]
Antidilutive securities (in shares)		1,233,973	1,166,998
2021 Notes [Member]
Antidilutive securities (in shares)			4,481,182
January 2020 Note [Member]
Antidilutive securities (in shares)		526,674
The 2019 Notes [Member]
Antidilutive securities (in shares)	[1]	19,943,828
Share-based Payment Arrangement [Member]
Antidilutive securities (in shares)		6,323,822	5,117,655
Warrants to Purchase Common Stock [Member]
Antidilutive securities (in shares)		2,423,077	2,527,763
Series A Convertible Preferred Stock [Member]
Antidilutive securities (in shares)			1,112,334

[1] Inclusive of 10,439,015 of shares of Common Stock issuable (i) in exchange of the Deerfield Optional Conversion Feature, or (ii) upon conversion of the Series B-2 Preferred Stock issuable in exchange of the Deerfield Optional Conversion Feature.