Note 5 - Leases (Details Textual)		1 Months Ended	3 Months Ended
	Apr. 01, 2021 USD ($)	Jan. 31, 2021 USD ($) a	Mar. 31, 2022 USD ($) ft²	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Operating Lease, Weighted Average Discount Rate, Percent			14.50%
Operating Lease, Right-of-Use Asset			$ 808,000		$ 847,000
Operating Lease, Liability, Total			1,181,000		$ 1,298,000
Lease, Cost, Total			$ 154,000	$ 154,000
Operating Lease, Weighted Average Remaining Lease Term (Year)			1 year 3 months 29 days
Operating Lease, Payments			$ 162,000	$ 166,000
Headquarters in San Diego, California [Member]
Area of Real Estate Property (Square Foot)		8,511	500
Monthly Lease Expense		$ 28,000	$ 2,000
Monthly Sublease Payments	$ 26,000