Note 7 - Accrued Expenses - Summary of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued legal and professional fees	$ 1,889	$ 1,305
Accrued payroll and related costs	2,795	2,871
Accrued contract manufacturing costs	5,114	2,516
Accrued clinical trial costs	1,489	2,318
Accrued consulting costs	1,117	862
Other	699	661
Accrued expenses	$ 13,103	$ 10,533