Note 10 - Share-based Compensation - Summary of RSU Activity (Details) - Restricted Stock Units (RSUs) [Member]	3 Months Ended
	Mar. 31, 2022 $ / shares shares
Awards other than options, unvested, beginning balance (in shares) | shares	269,303
Awards other than options, unvested, weighted average grant date fair value, beginning balance (in dollars per share) | $ / shares	$ 6.47
Awards other than options, Granted (in shares) | shares	160,779
Awards other than options, granted, weighted average grant date fair value (in dollars per share) | $ / shares	$ 2.41
Awards other than options, Vested (in shares) | shares	(49,252)
Awards other than options, vested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 4.72
Awards other than options, Forfeited and cancelled (in shares) | shares	(23,357)
Awards other than options, forfeited and cancelled, weighted average grant date fair value (in dollars per share) | $ / shares	$ 4.19
Awards other than options, unvested, ending balance (in shares) | shares	357,473
Awards other than options, unvested, weighted average grant date fair value, ending balance (in dollars per share) | $ / shares	$ 5.03
Weighted average vesting period (Year)	2 years 18 days