Note 4 - Balance Sheet Components (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Accounts Receivable, after Allowance for Credit Loss, Current, Total	$ 190,000		$ 190,000		$ 334,000
Accounts Receivable, Allowance for Credit Loss, Current	0		0		0
Depreciation, Total	211,000	$ 34,000	406,000	$ 78,000
Impairment of Property and Equipment			0	0
Amortization of Intangible Assets, Total	433,000	$ 433,000	$ 1,300,000	$ 1,300,000
Developed Technology Rights [Member]
Finite-Lived Intangible Asset, Remaining Life (Year)			8 years 1 month 6 days
Intellectual Property [Member]
Finite-Lived Intangible Asset, Useful Life (Year)			20 years
Finite-Lived Intangible Asset, Remaining Life (Year)			6 years 3 months
Minimum [Member] | Developed Technology Rights [Member]
Finite-Lived Intangible Asset, Useful Life (Year)			1 year 3 months 18 days
Maximum [Member] | Developed Technology Rights [Member]
Finite-Lived Intangible Asset, Useful Life (Year)			11 years 9 months
Royalty [Member]
Accounts Receivable, after Allowance for Credit Loss, Current, Total	$ 190,000		$ 190,000		$ 334,000