Note 9 - Net Loss Per Share of Common Stock - Summary of Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Net loss	$ (13,057)	$ (8,004)
Net loss per share - basic and diluted (in dollars per share)	$ (0.62)	$ (0.44)
Weighted-average shares used to compute basic and diluted net loss per share (in shares)	21,130	18,067