Note 14 - Stockholders' Equity (Details Textual) - USD ($)					1 Months Ended	12 Months Ended
	Dec. 06, 2019	Dec. 24, 2018	Dec. 21, 2018	Apr. 04, 2018	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Common Stock, Shares, Issued, Total					41,091,606	41,091,606	32,133,263
Proceeds from Issuance of Private Placement						$ 22,982,000	$ 32,893,000
The 2011 Long-term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized		4,200,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant					448,000	448,000	1,453,000
Series I Warrants Issued with Offering [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	4,375,002
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 4.03
Warrants and Rights Outstanding, Term	5 years
Common Stock Maximum Ownership Percentage For Warrant Exercise	4.99%
Common Stock Maximum Ownership Percentage For Warrant Exercise, Per Each Holder	19.99%
Conversion of Loan Payable as Part of Private Placement Financing [Member]
Debt Conversion, Original Debt, Amount	$ 2,950,000				$ 2,950,000
Private Placement [Member]
Stock Issued During Period, Shares, New Issues	8,749,999
Shares Issued, Price Per Share	$ 3.02
Proceeds from Issuance of Common Stock	$ 26,400,000
Common Stock, Shares, Issued, Total			11,785,540
Share Price			$ 3.3132
Proceeds from Issuance of Private Placement			$ 39,000,000
Private Placement [Member] | Lee’s Pharmaceutical Holdings Limited [Member]
Debt Conversion, Original Debt, Amount			6,000,000
Private Placement [Member] | Battelle [Member]
Debt Conversion, Original Debt, Amount			$ 1,000,000
Private Placement [Member] | LPH II [Member]
Stock Issued During Period, Shares, New Issues				541,667
Shares Issued, Price Per Share				$ 4.80
Class of Warrant or Right, Number of Securities Called by Warrants or Rights				135,417
Class of Warrant or Right, Exercise Price of Warrants or Rights				$ 5.52
Warrants and Rights Outstanding, Term				7 years
Private Placement, Purchase Price of Common Stock and Warrants				$ 2,600,000
Class of Warrant or Right, Vesting Period				180 days
Private Placement [Member] | Series F Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights			2,003,541
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 3.68
Warrants and Rights Outstanding, Term			1 year 180 days
Private Placement [Member] | Series G Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights			3,889,229
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 4.05
Warrants and Rights Outstanding, Term			5 years
Private Placement [Member] | December 2018 Warrants [Member]
Common Stock Maximum Ownership Percentage For Warrant Exercise			9.99%