Note 12 - Fair Value Measurements - Fair Value of Liabilities on a Recurring Basis (Details) - Fair Value, Measurements, Recurring [Member] $ in Thousands	Dec. 31, 2017 USD ($)
Warrant liabilities	$ (2,387)
Total warrant liabilities	(2,387)
Fair Value, Inputs, Level 1 [Member]
Warrant liabilities
Total warrant liabilities
Fair Value, Inputs, Level 2 [Member]
Warrant liabilities
Total warrant liabilities
Fair Value, Inputs, Level 3 [Member]
Warrant liabilities	(2,387)
Total warrant liabilities	$ (2,387)