Note 2 - Summary of Significant Accounting Policies (Details Textual) - USD ($)		3 Months Ended	6 Months Ended
	Aug. 30, 2019	Jun. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Contract with Customer, Liability, Revenue Recognized		$ 144,000	$ 432,000
Deferred Revenue, Current, Total		787,000	787,000	$ 620,000
Deferred Revenue, Noncurrent, Total		1,739,000	1,739,000	$ 1,901,000
Exclusivity Fee [Member]
Deferred Revenue, Current, Total		286,000	286,000
Deferred Revenue, Noncurrent, Total		1,476,000	1,476,000
Deferred Revenue, Total		1,762,000	1,762,000
Exclusivity Fee [Member]
Contract with Customer, Liability, Revenue Recognized		$ 71,000	$ 143,000
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