Note 12 - Equity Incentive Plan - Stock Options (Details) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($) $ / shares shares
Outstanding, shares (in shares) | shares	1,175,993
Outstanding, Weighted Average Exercise (in dollars per share) | $ / shares	$ 39.56
Granted, shares (in shares) | shares	464,775
Granted, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 23.21
Exercised, shares (in shares) | shares	(437)
Exercised, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 9.10
Exercised, Aggregate Intrinsic Value | $	$ 10
Forfeited and canceled, shares (in shares) | shares	(130,925)
Forfeited and canceled, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 44.25
Outstanding, shares (in shares) | shares	1,509,406
Outstanding, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 35.53
Outstanding, Weighted Average Remaining Contractual Term (Year)	8 years 6 months
Outstanding, Aggregate Intrinsic Value | $	$ 21
Vested, shares (in shares) | shares	459,732
Vested, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 40.07
Vested, Weighted Average Remaining Contractual Term (Year)	7 years 6 months
Vested, Aggregate Intrinsic Value | $	$ 7
Vested and expected to vest, shares (in shares) | shares	1,509,406
Vested and expected to vest, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 35.53
Vested and expected to vest, Weighted Average Remaining Contractual Term (Year)	8 years 6 months
Vested and expected to vest, Aggregate Intrinsic Value | $	$ 21