Note 9 - Debt - Information Pertaining to Convertible Notes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Balance
Original issue discount paid with 2020/21 Notes			282
Change in fair value of 2020/21 Notes embedded derivative	$ 176	$ (148)	276	$ (394)
Balance	276		276
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			(2,572)
Balance	276		276
Convertible Debt [Member]
Balance			(123)
Balance			(30)
Balance			13,900
Amortization of debt discount			187
Amortization of debt issue costs			15
Paid-in-kind interest			191
Original issue discount paid with 2020/21 Notes			(282)
Balance	(218)		(218)
Balance	(15)		(15)
Balance	14,293		14,293
Convertible 2020 Notes [Member]
Balance			13,900
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]
Balance	14,293		14,293
Convertible 2020/21 Notes [Member] | Convertible Debt [Member]
Balance
Paid-in-kind interest			144
Exchange of 2020 Notes for 2020/21 Notes			14,100
Original issue discount paid with 2020/21 Notes			282
Balance	14,526		14,526
Convertible Debt and Embedded Derivative Liabilities [Member]
Balance			13,900
Amortization of debt discount			187
Amortization of debt issue costs			15
Paid-in-kind interest			191
Fair value of 2020/21 embedded derivative			2,848
Change in fair value of 2020/21 Notes embedded derivative			(2,572)
Balance	$ 14,569		$ 14,569