Quarterly report pursuant to Section 13 or 15(d)

Note 1 - The Company and Basis of Presentation (Details Textual)

v3.10.0.1
Note 1 - The Company and Basis of Presentation (Details Textual) - USD ($)
3 Months Ended 9 Months Ended 11 Months Ended
Feb. 12, 2018
Nov. 08, 2017
Mar. 22, 2017
Sep. 30, 2018
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Jan. 01, 2018
Dec. 31, 2017
[1]
Dec. 31, 2016
Proceeds from Issuance of Common Stock         $ 33,407,000 $ 31,440,000        
Cash and Cash Equivalents, at Carrying Value, Ending Balance       $ 20,097,000 20,097,000 $ 19,207,000 $ 20,097,000   $ 20,730,000 $ 8,086,000
Working Capital       23,578,000 23,578,000   23,578,000      
Retained Earnings (Accumulated Deficit), Ending Balance       $ (141,893,000) $ (141,893,000)   $ (141,893,000) $ (105,404,000) $ (105,581,000)  
February 2018 Offering [Member]                    
Stock Issued During Period, Shares, New Issues 11,500,000                  
Share Price $ 3                  
Proceeds from Issuance of Common Stock $ 34,500,000                  
Proceeds From Issuance of Common Stock, Net $ 32,213,000                  
November 2017 ATM Facility [Member]                    
Stock Issued During Period, Shares, New Issues       3,720 277,249   336,498      
Proceeds From Issuance of Common Stock, Net       $ 10,100 $ 1,194,000   $ 1,318,000      
Aggregate Offering Price   $ 25,000,000                
March 2017 Offering [Member]                    
Stock Issued During Period, Shares, New Issues     8,625,000              
Share Price     $ 4              
Proceeds from Issuance of Common Stock     $ 34,500,000              
Proceeds From Issuance of Common Stock, Net     $ 31,440,000              
[1] The condensed consolidated balance sheet as of December 31, 2017 has been derived from the audited consolidated financial statements as of that date.