Annual report pursuant to Section 13 and 15(d)

Organization and Description of Business Operations (Details Textual)

v3.19.1
Organization and Description of Business Operations (Details Textual) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 12 Months Ended
Mar. 31, 2018
Dec. 31, 2018
Dec. 31, 2017
Retained Earnings (Accumulated Deficit)   $ (95,397) $ (59,030)
Payments of Stock Issuance Costs   $ 2,184 $ 0
National Securities Corporation [Member]      
Payments of Stock Issuance Costs $ 1,800    
Underwritten Public Offering [Member]      
Stock Issued During Period, Shares, New Issues 5,290,000    
Shares Issued, Price Per Share $ 4.35    
Stock Issued During Period, Value, New Issues $ 23,000    
Proceeds from Issuance Underwritten Public Offering 20,800    
Payments of Stock Issuance Costs $ 2,200    
Common Stock [Member]      
Shares Issued, Price Per Share   $ 4.33  
Stock Issued During Period Shares Common Shares For At The Market Offering   1,841,774  
Stock Issued During Period Value Common Shares For At The Market Offering Gross   $ 8,000  
Stock Issued During Period Value Common Shares For At The Market Offering Net   $ 7,700