Note 9 - Fair Value Measurement - Change in Level 3 Financial Liabilities Fair Value (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Conversion Feature Liability [Member]
Derivatives:
Balance beginning of year	$ (901,243)	$ (2,944,402)
Net realized gains/(losses)	0	29,875
Net unrealized gains/(losses) relating to instruments still held at the reporting date	(1,412,085)	2,013,284
Net purchases, issuances and settlements	0	0
Net transfers in and/or out of Level 3	0	0
Balance, end of period	(2,313,328)	(901,243)
Net realized gains/(losses)	0	29,875
Net unrealized gains/(losses) relating to instruments still held at the reporting date	(1,412,085)	2,013,284
Net purchases, issuances and settlements	0	0
Net transfers in and/or out of Level 3	0	0
Warrant Liability [Member]
Derivatives:
Balance beginning of year	(1,914,923)	(6,695,060)
Net realized gains/(losses)	0	0
Net unrealized gains/(losses) relating to instruments still held at the reporting date	(1,046,751)	2,482,639
Net purchases, issuances and settlements	(851,016)	(868,128)
Net transfers in and/or out of Level 3	0	3,165,626
Balance, end of period	(3,812,690)	(1,914,923)
Net realized gains/(losses)	0	0
Net unrealized gains/(losses) relating to instruments still held at the reporting date	(1,046,751)	2,482,639
Net purchases, issuances and settlements	(851,016)	(868,128)
Net transfers in and/or out of Level 3	0	3,165,626
Balance beginning of year	(2,816,166)	(9,639,462)
Net realized gains/(losses)	0	29,875
Net unrealized gains/(losses) relating to instruments still held at the reporting date	(2,458,836)	4,495,923
Net purchases, issuances and settlements	(851,016)	(868,128)
Net transfers in and/or out of Level 3	0	3,165,626
Balance, end of period	(6,126,018)	(2,816,166)
Net realized gains/(losses)	0	29,875
Net unrealized gains/(losses) relating to instruments still held at the reporting date	(2,458,836)	4,495,923
Net purchases, issuances and settlements	(851,016)	(868,128)
Net transfers in and/or out of Level 3	$ 0	$ 3,165,626