Note 2 - Liquidity and Summary of Significant Accounting Principles - Summary of Concentration Risk (Details) - Customer Concentration Risk [Member]	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Sales Revenue, Net [Member] | Customer B [Member]
Concentration percentage	42.00%	22.00%	31.00%	28.00%
Sales Revenue, Net [Member] | Customer C [Member]
Concentration percentage	15.00%		12.00%
Sales Revenue, Net [Member] | Customer D [Member]
Concentration percentage		15.00%		10.00%
Sales Revenue, Net [Member] | Customer E [Member]
Concentration percentage			11.00%
Sales Revenue, Net [Member] | Customer F [Member]
Concentration percentage		13.00%
Accounts Receivable [Member] | Customer B [Member]
Concentration percentage			52.00%		12.00%
Accounts Receivable [Member] | Customer A [Member]
Concentration percentage					72.00%
Accounts Receivable [Member] | Customer C [Member]
Concentration percentage			14.00%