Note 9 - Debt (Tables)

12 Months Ended

Dec. 31, 2019

Notes Tables

Schedule of Debt [Table Text Block]

	Principal Amount of 2020 Notes			Debt Discount			Debt Issue Costs			Total 2020 Notes			2020 Notes Embedded Derivative			Total 2020 Notes and 2020 Notes Embedded Derivative
Balance - December 31, 2017	$	16,657		$	(2,501	)	$	(665	)	$	13,491		$	5,224		$	18,715
Amortization of debt discount		—			1,094			—			1,094			—			1,094
Amortization of debt issue costs		—			—			309			309			—			309
Paid-in-kind interest		304			—			—			304			—			304
Change in fair value of 2020 Notes embedded derivative		—			—			—			—			(2,637	)		(2,637	)
Conversion of 2020 Notes into common stock		(3,186	)		428			114			(2,644	)		(2,193	)		(4,837	)
Balance - December 31, 2018		13,775			(979	)		(242	)		12,554			394			12,948
Amortization of debt discount		—			856			—			856			—			856
Amortization of debt issue costs		—			—			212			212			—			212
Paid-in-kind interest		278			—			—			278			—			278
Change in fair value of 2020 Notes embedded derivative		—			—			—			—			(394	)		(394	)
Balance - December 31, 2019	$	14,053		$	(123	)	$	(30	)	$	13,900		$	—		$	13,900

Schedule of Long-term Debt Instruments [Table Text Block]

Equipment	$	321
Insurance		428
		749
Less current portion		(516	)
Long-term portion	$	233

Schedule of Maturities of Long-term Debt [Table Text Block]

Year ending December 31,	Amount
2020	$	516
2021		79
2022		60
2023		62
2024		32
	$	749