Note 9 - Debt - Information Pertaining to Convertible Notes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Balance
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net, Total	394	$ 2,637
Gain from change in fair value of 2020 Notes embedded derivative	394	2,637
Balance	13,900
Embedded Derivative, 2020 Convertible Notes [Member]
Balance	394	5,224
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net, Total	(394)	(2,637)
Conversion of 2020 Notes into common stock		(2,193)
Gain from change in fair value of 2020 Notes embedded derivative	(394)	(2,637)
The 2020 Notes and 2020 Notes Embedded Derivative [Member]
Balance	12,948	18,715
Amortization of debt discount	856	1,094
Amortization of debt issue costs	212	309
Paid-in-kind interest	278	304
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net, Total	(394)	(2,637)
Conversion of 2020 Notes into common stock		(4,837)
Gain from change in fair value of 2020 Notes embedded derivative	(394)	(2,637)
Balance	13,900	12,948
Convertible 2020 Notes [Member]
Balance	13,775	16,657
Balance	(979)	(2,501)
Balance	(242)	(665)
Balance	12,554	13,491
Amortization of debt discount	856	1,094
Amortization of debt issue costs	212	309
Paid-in-kind interest	278	304
Conversion of 2020 Notes into common stock		(3,186)
Conversion of 2020 Notes into common stock		428
Conversion of 2020 Notes into common stock		114
Conversion of 2020 Notes into common stock		(2,644)
Balance	14,053	13,775
Balance	(123)	(979)
Balance	(30)	(242)
Balance	$ 13,900	$ 12,554