Note 7 - Fair Value Measurements - Fair Value of Liabilities on a Recurring Basis (Details) $ in Thousands	Mar. 31, 2020 USD ($)
Warrant derivative liabilities	$ 2,547
Total warrant derivative liabilities	2,547
Fair Value, Inputs, Level 1 [Member]
Warrant derivative liabilities
Total warrant derivative liabilities
Fair Value, Inputs, Level 2 [Member]
Warrant derivative liabilities
Total warrant derivative liabilities
Fair Value, Inputs, Level 3 [Member]
Warrant derivative liabilities	2,547
Total warrant derivative liabilities	$ 2,547