Note 7 - Accrued Expenses - Summary of Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Accrued legal and professional fees	$ 1,783	$ 1,889
Accrued payroll and related costs	1,241	2,795
Accrued contract manufacturing costs	1,906	5,114
Accrued clinical trial costs	1,805	1,489
Accrued consulting costs	554	1,117
Other	1,094	699
Accrued expenses	$ 8,383	$ 13,103