Note 14 - Equity Offerings - Summary of Sales Under Offering (Details) - The 2021 and 2020 ATM Offering [Member] $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) $ / shares shares
Total shares of common stock sold (in shares) | shares	20,237,045
Average price per share (in dollars per share) | $ / shares	$ 1.53
Gross proceeds	$ 30,943
Commisssion earned by Sales Agents	928
Net proceeds	$ 30,015