Note 9 - Debt - Information Pertaining to Convertible Notes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Balance
Original issue discount paid with 2020/21 Notes			282
Change in fair value of 2020/21 Notes embedded derivative	$ (247)		29	$ (394)
Balance	29		29
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			(2,819)
Balance	29		29
Convertible Debt [Member]
Balance			(123)
Balance			(30)
Balance			13,900
Amortization of debt discount			270
Amortization of debt issue costs			20
Paid-in-kind interest			316
Original issue discount paid with 2020/21 Notes			(282)
Conversion of 2020/21 Notes into common stock
Conversion of 2020/21 Notes into common stock
Conversion of 2020/21 Notes into common stock			(2,000)
Balance	(135)		(135)
Balance	(10)		(10)
Balance	12,506		12,506
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
Conversion of 2020/21 Notes into common stock
Balance
Convertible 2020/21 Notes [Member]
Balance	12,506		12,506
Convertible 2020/21 Notes [Member] | Convertible Debt [Member]
Balance
Paid-in-kind interest			269
Exchange of 2020 Notes for 2020/21 Notes			14,100
Original issue discount paid with 2020/21 Notes			282
Conversion of 2020/21 Notes into common stock			(2,000)
Balance	12,651		12,651
Convertible Debt and Embedded Derivative Liabilities [Member]
Balance			13,900
Amortization of debt discount			270
Amortization of debt issue costs			20
Paid-in-kind interest			316
Conversion of 2020/21 Notes into common stock			(2,000)
Fair value of 2020/21 embedded derivative			2,848
Change in fair value of 2020/21 Notes embedded derivative			(2,819)
Balance	$ 12,535		$ 12,535