Note 5 - Share-based Compensation - Stock Options (Details) - USD ($)		5 Months Ended	12 Months Ended
		Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019
2018 Equity Incentive Plan [Member]
Options outstanding, balance (in shares)			1,318,517
Options outstanding, granted (in shares)		1,318,517	7,895,839	1,318,517
Weighted average exercise price per share, granted (in dollars per share)		$ 0.30	$ 0.25
Options outstanding, expired (in shares)
Weighted average exercise price per share, balance (in dollars per share)		$ 0.30	$ 0.25	$ 0.30	$ 0.25
Options outstanding, balance (in shares)		1,318,517	9,214,356	1,318,517
Options outstanding, non-vested (in shares)					(4,097,996)
Weighted average exercise price per share, non-vested (in dollars per share)					$ 0.29
Options outstanding, vested (in shares)					5,116,360
Weighted average price per share, vested (in dollars per share)					$ 0.39
Aggregate Intrinsic Value	[1]				$ 97,000
Weighted average price per share, balance (in dollars per share)			$ 0.30
Options outstanding, expired (in shares)
Weighted average price per share, balance (in dollars per share)		$ 0.30	0.25	$ 0.30
2018 Equity Incentive Plan [Member] | Minimum [Member]
Exercise price per share, granted (in dollars per share)		0.22	0.16
Exercise price per share, balance (in dollars per share)		0.22	0.16	0.22	$ 0.16
Exercise price per share, non-vested (in dollars per share)			0.17
Exercise price per share, vested (in dollars per share)					0.16
Exercise price per share, balance (in dollars per share)			0.22
Exercise price per share, balance (in dollars per share)		0.22	0.16	0.22
2018 Equity Incentive Plan [Member] | Maximum [Member]
Exercise price per share, granted (in dollars per share)		0.43	0.40
Exercise price per share, balance (in dollars per share)		0.43	0.43	0.43	0.43
Exercise price per share, non-vested (in dollars per share)			0.45
Exercise price per share, vested (in dollars per share)					0.45
Exercise price per share, balance (in dollars per share)			0.43
Exercise price per share, balance (in dollars per share)		0.43	$ 0.43	$ 0.43
Non Plan [Member]
Options outstanding, balance (in shares)			19,319,496	20,018,408
Options outstanding, granted (in shares)			1,226,586	1,701,088
Exercise price per share, granted (in dollars per share)			$ 0.32	$ 0.43
Weighted average exercise price per share, granted (in dollars per share)			$ 0.21	$ 0.26
Options outstanding, expired (in shares)			941,975	2,400,000
Exercise price per share, balance (in dollars per share)		1	$ 1	$ 1	1
Weighted average exercise price per share, balance (in dollars per share)		$ 0.43	$ 0.41	$ 0.43	$ 0.41
Options outstanding, balance (in shares)		19,319,496	19,604,107	19,319,496
Options outstanding, non-vested (in shares)					(3,378,472)
Exercise price per share, non-vested (in dollars per share)
Weighted average exercise price per share, non-vested (in dollars per share)					$ 0.45
Options outstanding, vested (in shares)					16,225,635
Exercise price per share, vested (in dollars per share)					$ 1
Weighted average price per share, vested (in dollars per share)					$ 0.43
Aggregate Intrinsic Value	[2]				$ 30,000
Exercise price per share, balance (in dollars per share)			1	$ 1
Weighted average price per share, balance (in dollars per share)			$ 0.43	$ 0.51
Options outstanding, expired (in shares)			(941,975)	(2,400,000)
Exercise price per share, expired (in dollars per share)			$ 0.55
Weighted average price per share, expired (in dollars per share)			0.52	0.99
Exercise price per share, balance (in dollars per share)		$ 1	1	1
Weighted average price per share, balance (in dollars per share)		0.43	0.41	0.43
Non Plan [Member] | Minimum [Member]
Exercise price per share, granted (in dollars per share)			0.16	0.23
Exercise price per share, balance (in dollars per share)		0.23	0.16	0.23	$ 0.16
Exercise price per share, non-vested (in dollars per share)
Exercise price per share, vested (in dollars per share)					0.23
Exercise price per share, balance (in dollars per share)			0.23	0.25
Exercise price per share, expired (in dollars per share)			0.45
Exercise price per share, balance (in dollars per share)		0.23	0.16	0.23
Non Plan [Member] | Maximum [Member]
Exercise price per share, granted (in dollars per share)
Exercise price per share, balance (in dollars per share)
Exercise price per share, non-vested (in dollars per share)			0.45
Exercise price per share, vested (in dollars per share)
Exercise price per share, balance (in dollars per share)
Exercise price per share, expired (in dollars per share)				0.99
Exercise price per share, balance (in dollars per share)

[1] Aggregate intrinsic value based on closing common stock price of $0.22 at December 31, 2019.

[2] Aggregate intrinsic value based on closing common stock price of $0.22 at December 31, 2019.