Note 22 - Subsequent Events (Details Textual) - USD ($) $ / shares in Units, $ in Thousands				1 Months Ended	2 Months Ended	12 Months Ended
	Jan. 29, 2021	Jan. 12, 2021	Jul. 06, 2020	Jan. 31, 2021	Mar. 11, 2021	Dec. 31, 2020	Dec. 31, 2019	Apr. 28, 2017
Shares Issued, Price Per Share (in dollars per share)								$ 1.00
Stock Issued During Period, Value, New Issues						$ 33,846	$ 25,777
Proceeds from Warrant Exercises						3,340	$ 538
Public Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares)			42,857,142
Shares Issued, Price Per Share (in dollars per share)			$ 0.35
Stock Issued During Period, Value, New Issues						$ 13,477
Subsequent Event [Member]
Proceeds from Warrant Exercises					$ 30,400
Subsequent Event [Member] | Registered Direct Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares)		25,000,000
Shares Issued, Price Per Share (in dollars per share)		$ 1.25
Stock Issued During Period, Value, New Issues		$ 31,250
Proceeds from Issuance of Common Stock		$ 28,800		$ 28,800
Subsequent Event [Member] | Public Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares)	26,725,832
Shares Issued, Price Per Share (in dollars per share)	$ 3.00
Proceeds from Issuance of Common Stock	$ 73,500			$ 73,500