Note 2 - Summary of significant accounting policies (Tables)

12 Months Ended

Dec. 31, 2012

Property, Plant, and Equipment Useful Lives [Table Text Block]

Asset Category	Estimated Useful Life (in Years)
Laboratory equipment		5
Furniture and fixtures		5
Computer equipment		3

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	For the year ended December 31,
	2012				2011				2010
Risk-free interest rate		.65	-	1.49%		.96	-	2.61%		1.42	-	2.75%
Expected dividend yield				0%				0%				0%
Expected life - years		5	-	6		5	-	6		5	-	6
Expected volatility		86.58	-	92.60%		84.28	-	92.38%		84.23	-	89.55%

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

	As of December 31,
Common Equivalent Securities	2012		2011		2010
Warrants		10,377,995		12,564,193		9,450,633
Options		5,016,966		4,117,979		3,264,440
Total		15,394,961		16,682,172		12,715,073