Note 2 - Earnings Per Share - Securities that Potentially Dilute Calculation of Diluted Earnings Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Antidilutive securities (in shares)	35,335,901	14,151,732
Warrant [Member]
Antidilutive securities (in shares)	7,192,373	14,017,373
Warrants Classified as Equity [Member]
Antidilutive securities (in shares)	1,393	1,393
Convertible 2017 Notes [Member]
Antidilutive securities (in shares)		47,827
Convertible 2020 Notes [Member]
Antidilutive securities (in shares)	28,093,500
Convertible 2022 Notes [Member]
Antidilutive securities (in shares)		688
Employee Stock Option [Member]
Antidilutive securities (in shares)	46,431	76,915
Restricted Stock [Member]
Antidilutive securities (in shares)	2,204	7,536