Note 9 - Stock-based Compensation - Summary Stock Option Activity (Details) - $ / shares shares in Thousands	9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023
Shares Outstanding, Beginning Balance (in shares)	78
Weighted Average Exercise Price, Outstanding, at Beginning Period (in dollars per share)	$ 381
Shares Granted (in shares)	213
Weighted Average Exercise Price, Granted (in dollars per share)	$ 1.21
Shares Forfeited or Expired (in shares)	(12)
Weighted Average Exercise Price, Forfeited or Expired (in dollars per share)	$ 259.02
Shares Outstanding, Ending Balance (in shares)	279
Weighted Average Exercise Price, Outstanding, at Ending Period (in dollars per share)	$ 93.29
Weighted Average Remaining Contractual Life, Outstanding (Year)	9 years
Shares Vested and Exercisable (in shares)	57
Weighted Average Exercise Price, Vested and Exercisable (in dollars per share)	$ 434.41
Weighted Average Remaining Contractual Life, Vested and Exercisable (Year)	6 years
Vested and expected to vest (in shares)	259
Weighted Average Exercise Price, Vested and Expected to Vest (in dollars per share)		$ 94.61
Weighted Average Remaining Contractual Life, Vested and Expected to Vest (Year)	9 years