Note 9 - Common Stock (Details Textual)		1 Months Ended	12 Months Ended
	Jan. 09, 2013 USD ($) shares	Nov. 30, 2014 USD ($) $ / shares shares	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Jul. 31, 2013 USD ($)
Shares Earned Upon Execution Of The Revised Agreement [Member]
Common Stock, Capital Shares Reserved for Future Issuance	100,000
Shares Earned Upon Receipt By The Company [Member]
Common Stock, Capital Shares Reserved for Future Issuance	100,000
Shares Earned Upon The Signing Of Binding Agreements [Member]
Common Stock, Capital Shares Reserved for Future Issuance	100,000
Shares Earned Upon The Commencement Of Construction [Member]
Common Stock, Capital Shares Reserved for Future Issuance	100,000
Compensation Payment per Month [Member]
Compensation | $	$ 25,000
Percentage Of Present Value Of Project Paid As Incentive Compensation	1.00%
Common Stock, Capital Shares Reserved for Future Issuance	400,000
Percentage Of Projects Annual Capacity	51.00%
Number of Milestones for Common Stock Issuance	4
Shares Payable Term From Date Earned	3 years
Share-based Compensation | $	$ 373,000		$ 1,116,000	$ 1,077,000	$ 516,000
Shelf Registration Value | $						$ 40,000,000
Proceeds from Issuance of Common Stock | $		$ 14,600,000		$ 14,523,000
Stock Issued During Period, Shares, New Issues		1,435,713
Shares Issued, Price Per Share | $ / shares		$ 10.1751