Note 6 - Leases - Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
2019 (remaining nine months)	$ 957
2020	859
2021	254
2022	193
2023	58
Total remaining lease payments	2,321
Less: imputed interest	(167)
Total lease liabilities	2,154
Current liabilities	1,158
Long-term liabilities	$ 996