Note 4 - Property and Equipment, Net (Details Textual) - USD ($)
|12 Months Ended|
Dec. 31, 2018
Dec. 31, 2017
|Depreciation, Total||$ 786,000||$ 449,000|
The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.
Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef