Note 9 - Fair Value Measurement (Details) - Change in Level 3 Financial Liabilities Fair Value - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Derivatives:
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	(762,011)	4,495,923
Net purchases, issuances and settlements	(325,689)	(868,128)
Net transfers in and/or out of Level 3	0	3,165,626
Balance, end of period	(3,903,866)	(2,816,166)
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	(401,563)	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	(1,302,806)	(901,243)
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	(360,448)	2,482,639
Net purchases, issuances and settlements	(325,689)	(868,128)
Net transfers in and/or out of Level 3	0	3,165,626
Balance, end of period	$ (2,601,060)	$ (1,914,923)