Note 9 - Debt - Information Pertaining to Convertible Notes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Balance	$ 13,900
Balance
Original issue discount paid with 2020/21 Notes	282
Change in fair value of 2020/21 Notes embedded derivative	100	$ (246)
Balance	14,050
Balance	100
Embedded Derivative, Convertible Notes [Member]
Balance
Fair value of 2020/21 embedded derivative	2,848
Change in fair value of 2020/21 Notes embedded derivative	(2,748)
Balance	100
Convertible Debt [Member]
Balance	(123)
Balance	(30)
Balance	13,900
Amortization of debt discount	95
Amortization of debt issue costs	8
Paid-in-kind interest	47
Original issue discount paid with 2020/21 Notes	(282)
Balance	(310)
Balance	(22)
Balance	14,050
Convertible 2020 Notes [Member] | Convertible Debt [Member]
Balance	14,053
Paid-in-kind interest	47
Exchange of 2020 Notes for 2020/21 Notes	(14,100)
Original issue discount paid with 2020/21 Notes
Balance
Convertible 2020/21 Notes [Member] | Convertible Debt [Member]
Balance
Paid-in-kind interest
Exchange of 2020 Notes for 2020/21 Notes	14,100
Original issue discount paid with 2020/21 Notes	282
Balance	14,382
Convertible Debt and Embedded Derivative Liabilities [Member]
Balance	13,900
Amortization of debt discount	95
Amortization of debt issue costs	8
Paid-in-kind interest	47
Fair value of 2020/21 embedded derivative	2,848
Change in fair value of 2020/21 Notes embedded derivative	(2,748)
Balance	$ 14,150