Note 4 - Stockholders' Equity - Summary of Stock Option Activity (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Options Outstanding (in shares)	271,660
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 61.83
Weighted- average remaining contractual life (Year)	8 years 328 days	7 years 292 days
Options Granted (in shares)	648,724
Options Granted, Weighted Average Exercise Price (in dollars per share)	$ 0.62
Options Exercised (in shares)
Options Exercised, Weighted Average Exercise Price (in dollars per share)
Options Forfeited (in shares)
Options Forfeited, Weighted Average Exercise Price (in dollars per share)
Options Outstanding (in shares)	920,384	271,660
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 18.69	$ 61.83
Aggregate intrinsic value	$ 64,937
Options Exercisable (in shares)	424,861
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 38.97
Options Exercisable, Weighted Average Remaining Contractual Life (Year)	8 years
Options Exercisable, Aggregate Intrinsic Value	$ 18,940