Note 9 - Net Loss Per Share of Common Stock (Tables)

9 Months Ended

Sep. 30, 2021

Notes Tables

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2021			2020			2021			2020
Net loss	$	(11,086	)	$	(10,660	)	$	(26,195	)	$	(26,497	)
Basic and diluted net loss per share	$	(0.53	)	$	(0.66	)	$	(1.33	)	$	(1.69	)
Weighted-average shares used to compute basic and diluted net loss per share		20,763			16,055			19,758			15,658

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

	Nine Months Ended
	September 30,
	2021		2020
Options to purchase common stock		2,433,675		2,204,141
Restricted stock units		—		1,441