Note 2 - Summary of Significant Accounting Policies (Details Textual) - USD ($)		3 Months Ended	9 Months Ended
	Aug. 30, 2019	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Contract with Customer, Liability, Revenue Recognized		$ 115,000	$ 547,000
Deferred Revenue, Current, Total		700,000	700,000	$ 620,000
Deferred Revenue, Noncurrent, Total		1,669,000	1,669,000	$ 1,901,000
Exclusivity Fee [Member]
Deferred Revenue, Current, Total		286,000	286,000
Deferred Revenue, Noncurrent, Total		1,404,000	1,404,000
Deferred Revenue, Total		1,690,000	1,690,000
Exclusivity Fee [Member]
Contract with Customer, Liability, Revenue Recognized		$ 71,000	$ 214,000
Exclusivity Fee Recognize Period (Year)			7 years
Supply Agreement [Member]
Supply Agreement, Term (Year)	5 years
Supply Agreement, Renewal Term (Year)	2 years		2 years
Contract with Customer, Liability, Total	$ 2,000,000
Proceeds from Customers			$ 2,000,000