STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($)
$ in Thousands
Common Stock [Member]
Additional paid-in capital [Member]
Receipts on account of shares [Member]
Accumulated Deficit [Member]
Total
Balance at Dec. 31, 2017 $ 11 $ 85,944 $ 0 $ (80,075) $ 5,880
Balance (in shares) at Dec. 31, 2017 18,976,169        
Stock-based compensation related to warrants and stock granted to service providers [1] 102 0 0 102
Stock-based compensation related to warrants and stock granted to service providers (in shares) 42,293        
Stock-based compensation related to stock and options granted to directors and employees [1] 917 0 0 917
Stock-based compensation related to stock and options granted to directors and employees (in shares) 147,820        
Exercise of options [1] 25 0 0 25
Exercise of options (in shares) 33,332        
Exercise and reissuance of warrants [1] 7,632 4,408 0 12,040
Exercise and reissuance of warrants (in shares) 1,558,202        
Net loss $ 0 0 0 (13,948) (13,948)
Balance at Dec. 31, 2018 $ 11 94,620 4,408 (94,023) 5,016
Balance (in shares) at Dec. 31, 2018 20,757,816        
Stock-based compensation related to warrants and stock granted to service providers [1] 25 0 0 25
Stock-based compensation related to warrants and stock granted to service providers (in shares) 5,908        
Stock-based compensation related to stock and options granted to directors and employees [1] 365 0 0 365
Stock-based compensation related to stock and options granted to directors and employees (in shares) 39,386        
Exercise of options [1] 5     5
Exercise of options (in shares) 5,333        
Exercise and reissuance of warrants [1] 4,408 (4,408)    
Exercise and reissuance of warrants (in shares) 899,999        
Net loss $ 0 0 0 (9,927) (9,927)
Balance at Jun. 30, 2019 $ 11 $ 99,423 $ 0 $ (103,950) $ (4,516)
Balance (in shares) at Jun. 30, 2019 21,708,442        
[1] Represents an amount less than $1.