Note 9 - Prepaid Forward Obligation - Activity in the Carrying Value of the Prepaid Forward Liability (Details) - USD ($) $ in Thousands	3 Months Ended		5 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020
Prepaid forward obligation at closing of RTW Transaction			$ 75,000	$ 0
Capitalized closing costs			(2,583)
Financing on prepaid forward obligation	$ 6,828	$ (0)	9,948	9,948	$ (0)
Amounts paid and payable			(2,438)
Carrying value of prepaid forward obligation as of September 30, 2021	$ 79,927		$ 79,927	$ 79,927