Note 3 - Fair Value of Financial Instruments (Details) - Summary of changes in the fair value of the Company’s Level 3 fair value measurements: (USD $)	6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012
Accrued Warrant Liability [Member] | Three Months [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 7,553,382		$ 5,566,203
Total (gains) or losses, realized and unrealized, included in earnings (1)(2)	(2,795,612)	[1]	(2,543,270)	[1]
Estimates and other changes in fair value		[2]		[2]
Balance,	4,757,770		3,022,933
Accrued Warrant Liability [Member] | Six Months [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	4,105,659		7,285,959
Total (gains) or losses, realized and unrealized, included in earnings (1)(2)	652,111	[1]	(4,263,026)	[1]
Estimates and other changes in fair value		[2]		[2]
Balance,	4,757,770		3,022,933
Compensatory Stock Options Not Yet Issued [Member] | Three Months [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	63,641		85,000
Total (gains) or losses, realized and unrealized, included in earnings (1)(2)		[1]		[1]
Estimates and other changes in fair value	197	[2]	29,617	[2]
Balance,	63,838		114,617
Compensatory Stock Options Not Yet Issued [Member] | Six Months [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance			378,750
Total (gains) or losses, realized and unrealized, included in earnings (1)(2)		[1]	51,823	[1]
Estimates and other changes in fair value	63,838	[2]	114,617	[2]
Settlements			(430,573)
Balance,	$ 63,838		$ 114,617

[1] Unrealized gains or losses related to the accrued warrant liability were included as change in value of accrued warrant liability.

[2] Expenses recorded for compensatory stock options not yet issued are included in research & development expense and general and administrative expense.