Note 2 - Long-term Debt (Details Textual) - USD ($)		3 Months Ended
	Mar. 05, 2020	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Apr. 26, 2016
Debt Instrument, Face Amount		$ 27,300,000
Debt Conversion, Original Debt, Amount		38,900,000
Gain (Loss) on Extinguishment of Debt, Total		$ (12,396,000)
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)		362,500
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 0.01	$ 6.75
Debt Instrument, Prepayment Premium, Percent	7.00%
Derivative Liability, Current	$ 2,000,000	$ 2,547,000
Current Period Reclassification Adjustment	$ 900,000
Unamortized Debt Issuance Expense		1,100
Fair Value Adjustment of Warrants		561,000
2017 Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	362,500
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 6.75
Preferred Class A [Member]
Debt Instrument, Convertible, Number of Common Shares per One Preferred Share (in shares)	405.05
2020 Convertible Senior Notes [Member]
Debt Instrument, Interest Rate, Stated Percentage					7.00%
Debt Instrument, Face Amount					$ 27,400,000
Conversion of Convertible Senior Notes 2020 into Preferred Stock [Member]
Debt Conversion, Original Debt, Amount	$ 27,300,000
Debt Conversion, Converted Instrument, Shares Issued (in shares)	10,000
Gain (Loss) on Extinguishment of Debt, Total		$ (12,400,000)
Conversion of Convertible Senior Notes 2020 into Common Stock [Member]
Debt Conversion, Original Debt, Amount	$ 17,500,000
Debt Conversion, Converted Instrument, Shares Issued (in shares)	2,600,000