Note 4 - Debt - Components of Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2019		Dec. 31, 2018		Oct. 12, 2016
Principal	$ 87,493		$ 80,691
Carrying amount	84,969		76,820	[1]
The 2017 Senior Credit Facility [Member]
Principal	32,000		27,000
Carrying amount	32,000		27,000
Convertible Second Lien Notes [Member]
Principal	55,493	[1]	53,691	[1]	$ 40,000
Carrying amount	$ 52,969	[1]	$ 49,820	[1]	$ 29,000

[1] The debt discount is being amortized using the effective interest rate method based upon a maturity date of August 30, 2019. The principal includes $15.5 million and $13.7 million of paid in-kind interest as of March 31, 2019 and December 31, 2018, respectively. The carrying value includes $2.5 million and $3.9 million of unamortized debt discount as of March 31, 2019 and December 31, 2018, respectively.