Note 9 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2022	Aug. 04, 2022	Dec. 31, 2021
Preferred Stock, Shares Authorized (in shares)	5,000,000		5,000,000
Preferred Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.0001		$ 0.0001
Preferred Stock, Shares Outstanding, Ending Balance (in shares)	0		0
Common Stock, Shares Authorized (in shares)	150,000,000		150,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.0001		$ 0.0001
Dividends, Total	$ 0
First Set of Warrants Expiring April 2024 [Member]
Warrant Exercise Price to be Entitled to Receive Cash Consideration, Fundamental Transaction (in dollars per share)	$ 1.10
Warrants Expiring March 2025 [Member]
Warrant Exercise Price to be Entitled to Receive Cash Consideration, Fundamental Transaction (in dollars per share)	2.50
Warrants Expiring February 2025 [Member]
Warrant Exercise Price to be Entitled to Receive Cash Consideration, Fundamental Transaction (in dollars per share)	$ 3.125
Subsequent Event [Member]
Common Stock, Shares Authorized (in shares)		250,000,000