5. Property and Equipment, net  | 
3 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Mar. 31, 2019  | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Property, Plant and Equipment [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Property and Equipment, net | 
 
 Property and equipment, net consists of the following: 
 
 Depreciation expense was approximately $1,000 and $6,000 for the three months ended March 31, 2019 and 2018, respectively.  | 
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