Note 9 - Stock-based Compensation - Restricted Stock Units (Details) - Restricted Stock Units (RSUs) [Member] shares in Thousands	9 Months Ended
	Sep. 30, 2023 $ / shares shares
Balance (in shares) | shares	11
Weighted- Average Grant Date Fair Value, Outstanding, Beginning Balance (in dollars per share) | $ / shares	$ 49.5
Awarded (in shares) | shares	142
Awarded, Weighted- Average Grant Date Fair Value, Outstanding (in dollars per share) | $ / shares	$ 1.21
Vested (in shares) | shares	(3)
Vested Weighted- Average Grant Date Fair Value, Outstanding (in dollars per share) | $ / shares	$ 48.55
Cancelled (in shares) | shares	(3)
Cancelled, Weighted- Average Grant Date Fair Value, Outstanding (in dollars per share) | $ / shares	$ 49.57
Balance (in shares) | shares	147
Weighted- Average Grant Date Fair Value, Outstanding (in dollars per share) | $ / shares	$ 2.94