Note 8 - Common and Preferred Stock (Details Textual)						12 Months Ended
	Jul. 02, 2021 USD ($) $ / shares	Jul. 01, 2021 USD ($) $ / shares shares	Jun. 29, 2021 $ / shares shares	Mar. 05, 2020 shares	Jan. 31, 2013 shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Jul. 02, 2026 $ / shares	Dec. 27, 2021 $ / shares
Common Stock, Shares Authorized (in shares)						70,000,000	70,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares						$ 0.01	$ 0.01
Common Stock, Shares, Issued, Total (in shares)						43,656,169	36,902,361
Common Stock, Capital Shares Reserved for Future Issuance (in shares)					400,000
Percentage Of Projects Annual Capacity					51.00%
Number of Milestones for Common Stock Issuance					2
Shares Payable Term From Date Earned (Year)					3 years
Preferred Stock, Shares Issued, Total (in shares)						329	7,531
Preferred Stock, Dividend Rate, Percentage						8.857%
Preferred Stock, Shares Authorized (in shares)						100,000	100,000
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares						$ 0.01	$ 0.01
Payments of Dividends, Total | $						$ 1,449,000	$ (0)
Common Stock, Shares, Outstanding, Ending Balance (in shares)						43,656,169	36,902,361
Preferred Stock, Shares Outstanding, Ending Balance (in shares)						329	7,531
Preferred Class A [Member]
Convertible Preferred Stock, Shares Issued upon Conversion (in shares)				405.05
Series 1 Preferred Stock [Member]
Conversion of Stock, Shares Converted (in shares)						9,671
Conversion of Stock, Shares Issued (in shares)						3,917,235
Preferred Stock, Shares Issued, Total (in shares)						329
Preferred Stock, Shares Outstanding, Ending Balance (in shares)						329
Depository Shares [Member]
Stock Issued During Period, Shares, New Issues (in shares)			2,000,000
Preferred Stock, Shares Per Depository Share (in dollars per share) | $ / shares			$ 0.001
Preferred Stock, Liquidation Preference Per Share (in dollars per share) | $ / shares	$ 25.00	$ 25.00	$ 25.00
Preferred Stock, Liquidation Preference Per Share Per Year		2.21875
Dividends Payable, Amount Per Share (in dollars per share) | $ / shares									$ 0.56
Depository Shares [Member] | Sale Including Overallotment Option [Member]
Stock Issued During Period, Shares, New Issues (in shares)			2,000,000
Sale Including Overallotment Option [Member] | Sale Including Overallotment Option [Member] | Maximum [Member]
Stock Issued During Period, Shares, New Issues (in shares)			300,000
Series A Preferred Stock [Member]
Preferred Stock, Shares Issued, Total (in shares)						2,300	0
Preferred Stock, Dividend Rate, Percentage	8.875%	8.875%	8.875%			8.875%	8.875%
Proceeds From Issuance of Preferred Stock, Net of Issuance Costs | $	$ 54,000,000
Preferred Stock, Shares Authorized (in shares)		7,500				7,500	0
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares		$ 0.01				$ 0.01	$ 0.01
Preferred Stock, Liquidation Preference, Value | $		$ 25,000.00
Preferred Stock, Liquidation Preference Per Share (in dollars per share) | $ / shares			$ 25,000.00
Preferred Stock, Liquidation Preference Per Share Per Year		2,218.75
Dividends Payable, Amount Per Share (in dollars per share) | $ / shares									$ 560.00
Conversion of Stock, Shares Cap (in shares)		3,748.13
Preferred Stock, Shares Outstanding, Ending Balance (in shares)						2,300	0
Conversion of Convertible Senior Notes 2020 into Preferred Stock [Member]
Debt Conversion, Converted Instrument, Shares Issued (in shares)				10,000
Water Project with Brownstein [Member]
Related Party Transaction, Expenses from Transactions with Related Party | $						$ 2,200,000	$ 1,500,000
Shares Earned Upon The Signing Of Binding Agreements [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in shares)					100,000
Shares Earned Upon The Commencement Of Construction [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in shares)					100,000
Forecast [Member] | Depository Shares [Member]
Preferred Stock, Redemption Price Per Share (in dollars per share) | $ / shares								$ 25.00
Forecast [Member] | Series A Preferred Stock [Member]
Preferred Stock, Redemption Price Per Share (in dollars per share) | $ / shares								$ 25,000.00
Upon Change of Control [Member] | Depository Shares [Member]
Preferred Stock, Redemption Price Per Share (in dollars per share) | $ / shares		$ 25.00
Upon Change of Control [Member] | Series A Preferred Stock [Member]
Preferred Stock, Redemption Price Per Share (in dollars per share) | $ / shares		$ 25,000.00