Note 2 - Summary of Significant Accounting Policies - Revenues and Accounts Receivable From Major Distribution Partners and Customers (Details) - Customer Concentration Risk [Member]	12 Months Ended
	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Revenue from Contract with Customer Benchmark [Member] | Distributor A [Member]
Distribution or collaboration partners	16.00%		23.00%		22.00%
Revenue from Contract with Customer Benchmark [Member] | Distributor B [Member]
Distribution or collaboration partners	17.00%		26.00%		23.00%
Revenue from Contract with Customer Benchmark [Member] | Distributor C [Member]
Distribution or collaboration partners	15.00%		25.00%		21.00%
Revenue from Contract with Customer Benchmark [Member] | Distributor D [Member]
Distribution or collaboration partners		[1]		[1]	10.00%
Revenue from Contract with Customer Benchmark [Member] | Avenova Direct [Member]
Distribution or collaboration partners	15.00%
Accounts Receivable [Member] | Distributor A [Member]
Distribution or collaboration partners	28.00%		32.00%
Accounts Receivable [Member] | Distributor B [Member]
Distribution or collaboration partners	13.00%		31.00%
Accounts Receivable [Member] | Distributor C [Member]
Distribution or collaboration partners	19.00%		23.00%
Accounts Receivable [Member] | Avenova Direct [Member]
Distribution or collaboration partners	20.00%

[1] Not greater than 10%