Note 5 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Thousands			6 Months Ended
	Aug. 12, 2022	May 06, 2022	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Aug. 19, 2021
Common Stock, Shares Authorized (in shares)			300,000,000		300,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share)			$ 0.01		$ 0.01
Warrants exercise price						$ 3.45
Gross Proceeds			$ 1,775
Payment of equity issuance costs			$ 16	$ 0
May 2022 Registered Direct Offering
Common Stock, Par or Stated Value Per Share (in dollars per share)		$ 0.01
Offering shares (Per share)		3,646,690
Shares Issued, Price Per Share		$ 0.55
Warrants to purchase shares of common stock			3,646,690
Gross Proceeds		$ 1,400
Aggregate Consideration		2,000
Payment of equity issuance costs		$ 600
Stock Issued During Period, Shares, New Issues		3,646,690
May 2022 Purchase Warrants
Warrants to purchase shares of common stock		3,646,690
Warrants exercise price		$ 0.7105
May 2022 Placement Agent Warrants
Warrants to purchase shares of common stock		218,801
Warrants exercise price		$ 0.7105
August 2022 Public Offering | Subsequent Event [Member]
Offering shares (Per share)	42,160,000
Gross Proceeds	$ 12,000
Payment of equity issuance costs	1,500
Net Proceeds	$ 10,500
Stock Issued During Period, Shares, New Issues	42,160,000
August 2022 Public Offering | Warrant One [Member] | Subsequent Event [Member]
Warrants to purchase shares of common stock	48,000,000
Warrants exercise price	$ 0.25
Warrants term	1 year
August 2022 Public Offering | Warrant Two [Member] | Subsequent Event [Member]
Warrants to purchase shares of common stock	48,000,000
Warrants exercise price	$ 0.25
Warrants term	5 years
Common Stock [Member] | August 2022 Public Offering | Warrant Two [Member] | Subsequent Event [Member]
Warrants to purchase shares of common stock	1,000
Common Stock [Member] | August 2022 Public Offering | Warrant one and Warrant two [Member] | Subsequent Event [Member]
Common Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.25
Series B Convertible Preferred Stock [Member] | August 2022 Public Offering | Subsequent Event [Member]
Preferred stock, shares issued (in shares)	1,460
Series B Convertible Preferred Stock [Member] | August 2022 Public Offering | Warrant One [Member] | Subsequent Event [Member]
Convertible Preferred Stock, Issuable Upon Conversion of All Shares (in shares)	4,000
Series B Convertible Preferred Stock [Member] | August 2022 Public Offering | Warrant Two [Member] | Subsequent Event [Member]
Convertible Preferred Stock, Issuable Upon Conversion of All Shares (in shares)	4,000
Series C Preferred Stock [Member]
Preferred stock, shares issued (in shares)				317,420
Series C convertible preferred stock, shares outstanding (in shares)				11,674,131
Series A 4.5% Convertible Preferred Stock [Member]
Preferred Stock, Shares Authorized (in shares)					200,000
Preferred Stock, Par or Stated Value Per Share (in dollars per share)					$ 0.01
Series A 4.5% Convertible Preferred Stock [Member] | Private Placement [Member]
Convertible Preferred Stock, Issuable Upon Conversion of All Shares (in shares)			6,479
Series A Preferred Stock [Member]
Preferred Stock, Shares Authorized (in shares)			7,000,000		7,000,000
Preferred Stock, Par or Stated Value Per Share (in dollars per share)			$ 0.01		$ 0.01
Preferred stock, shares issued (in shares)			200,000
LBS [Member]
Common Stock, Shares Authorized (in shares)				6,797,500
Common Stock, Par or Stated Value Per Share (in dollars per share)				$ 0.01
Preferred Stock, Shares Authorized (in shares)				33,594,625
Preferred Stock, Par or Stated Value Per Share (in dollars per share)				$ 0.001