Note 2 - Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

	Year Ended December 31,
	201 8		201 7		201 6
Warrants to purchase common stock - liability classified		55,963		359,619		55,119
Warrants to purchase common stock - equity classified		6		70		70
Convertible 2017 Notes		–		–		3,756
Convertible 2020 Notes		1,071,674		1,437,984		–
Convertible 2022 Notes		–		–		280
Outstanding options to purchase common stock		2,311		2,322		846
Unvested restricted common stock		290,300		155		441
Stock appreciation rights		132,559		–		–
Total		1,552,813		1,800,150		60,512