Note 10 - Leases - Undiscounted Payments Under Non-cancelable Leases (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019		Dec. 31, 2018
Finance leases, remainder 2019	$ 136
Operating leases, remainder 2019	398
Finance leases, 2020	255
Operating leases, 2020	598
Finance leases, 2021	249
Operating leases, 2021	453
Finance leases, 2022	200
Operating leases, 2022	226
Finance leases, 2023	117
Operating leases, 2023	246
Finance leases, thereafter	8
Operating leases, thereafter	321
Finance leases, total minimum lease payments	965
Operating leases, total minimum lease payments	2,242
Finance leases, less: Amount representing interest	(79)
Operating leases, less: Amount representing interest	(218)
Present value of minimum finance lease payments	886			$ 880
Operating Lease, Liability, Total	2,024	$ 2,351
Finance leases, less: current maturities	(231)			(204)
Operating leases, less: current maturities	(663)	(699)	[1]
Finance leases obligations, net of current portion	655			$ 676
Operating lease obligations, net of current portion	$ 1,361	$ 1,652	[1]

[1] Represents the December 31, 2018 balance recorded at implementation of Topic 842