Note 2 - Summary of significant accounting policies (Detail) - Summary of antidilutive securities excluded from calculation of diluted net loss per share:	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Warrant [Member]
Common Equivalent Securities	10,377,995	12,564,193	9,450,633
Stock Option [Member]
Common Equivalent Securities	5,016,966	4,117,979	3,264,440
Total [Member]
Common Equivalent Securities	15,394,961	16,682,172	12,715,073