Note 6 - Fair Value of Measurements (Tables)

3 Months Ended

Mar. 31, 2013

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	Total Fair Value on the Balance Sheet		Quoted Prices In Active Markets For Identical Assets /Liabilities (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
As of March 31, 2013
Short-term investments available for sale
Bonds – corporate issuances	$	25,202,875	$	25,202,875	$	−	$	−
As of December 31, 2012
Short-term investments available for sale
Bonds – corporate issuances	$	8,037,620	$	8,037,620	$	−	$	−
Liabilities:
As of March 31, 2013
Common stock warrant liability	$	3,635	$	−	$	−	$	3,635
As of December 31, 2012
Common stock warrant liability	$	4,283,932	$	−	$	−	$	4,283,932