Note 7 - Warrants and Registration Rights Agreements (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Nov. 05, 2018	Jul. 31, 2018	Feb. 28, 2018	Feb. 06, 2018	Aug. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jul. 31, 2016	Mar. 21, 2016	Jan. 28, 2016
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	4,500,000	4,500,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 0.01	$ 0.01
Related Party November 2018 Note Payable To Great Harbor LLC [Member]
Class of Warrant or Right [Line Items]
Debt Instrument, Unamortized Discount, Total			$ 1,214
July 2018 GH Warrant [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)				2,500,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)				$ 0.01
Common Stock, Capital Shares Reserved for Future Issuance (in shares)				2,500,000
Debt Instrument, Unamortized Discount, Total				$ 1,479
November 2018 Great Harbor Warrant [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)			$ 0.01		$ 0.01
Common Stock, Capital Shares Reserved for Future Issuance (in shares)			2,000,000		1,818,182
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)			2,000,000		1,818,182
Escrow Warrants [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding (in shares)	13,093,929
January 2016 Golisano Warrant [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)												$ 0.01
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)												1,136,363
March 2016 Golisano Warrant [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)											$ 0.01
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)											3,181,816
Little Harbor July 2016 Warrant [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)										$ 0.01
Common Stock, Capital Shares Reserved for Future Issuance (in shares)										2,168,178
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)										2,168,178
Golisano LLC December 2016 Warrant [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)									$ 0.01
Common Stock, Capital Shares Reserved for Future Issuance (in shares)									1,136,363
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)									1,136,363
Golisano LLC March 2017 Warrant [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)								$ 0.01
Common Stock, Capital Shares Reserved for Future Issuance (in shares)								1,484,847
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)								1,484,847
Golisano Warrants [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)										2,168,178
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)						$ 0.01				$ 0.01
Common Stock, Capital Shares Reserved for Future Issuance (in shares)						1,818,182				2,168,178
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)						1,818,182
January 2016 GH Warrant [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)												$ 0.01
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)												1,136,363
March 2016 GH Warrant [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)											$ 0.01
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)											3,181,816
December 2016 GH Warrant [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)									$ 0.01
Common Stock, Capital Shares Reserved for Future Issuance (in shares)									1,136,363
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)									1,136,363
August 2017 GH Warrant [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)							$ 0.01
Common Stock, Capital Shares Reserved for Future Issuance (in shares)							1,363,636
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)							1,363,636