Note 5 - Stock-based Compensation; Changes in Equity - Option Activity (Details)	6 Months Ended
	Jun. 30, 2020 $ / shares shares
Outstanding, beginning of period (in shares) | shares	471,144
Outstanding, beginning of period (in dollars per share) | $ / shares	$ 3.95
Granted (in shares) | shares	792,660
Granted (in dollars per share) | $ / shares	$ 1
Cancelled/Expired (in shares) | shares	(436,519)
Cancelled/Expired (in dollars per share) | $ / shares	$ 3.95
Exercised/Issued (in shares) | shares	(15,000)
Exercised/Issued (in dollars per share) | $ / shares	$ 5.48
Outstanding at the end of period (in shares) | shares	812,285
Outstanding at the end of period (in dollars per share) | $ / shares	$ 1.21
Exercisable at the end of period (in shares) | shares	19,625
Exercisable at the end of period (in dollars per share) | $ / shares	$ 5.49