Note 13 - Fair Value Measurements - Fair Value of Liabilities on a Recurring Basis (Details) - Fair Value, Recurring [Member] $ in Thousands	Dec. 31, 2020 USD ($)
Warrant liabilities	$ 1,847
Total warrant liabilities	1,847
Fair Value, Inputs, Level 1 [Member]
Warrant liabilities	0
Total warrant liabilities	0
Fair Value, Inputs, Level 2 [Member]
Warrant liabilities	0
Total warrant liabilities	0
Fair Value, Inputs, Level 3 [Member]
Warrant liabilities	1,847
Total warrant liabilities	$ 1,847