v3.19.1
Note 6 - Collaboration Agreement (Details Textual) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Dec. 31, 2018
 [1]
Jul. 17, 2015
Revenue Recognition Milestone Method Agreed, Additional Amount, Based On Efforts And Targets       $ 194,500
Revenue from Contract with Customer, Including Assessed Tax $ 265 $ 343    
Contract with Customer, Liability, Current 437   $ 315  
Contract with Customer, Liability, Noncurrent 3,069   $ 3,148  
Collaboration Agreement Revenue [Member]        
Revenue from Contract with Customer, Including Assessed Tax 218 $ 274    
Contract with Customer, Liability, Current 300      
Contract with Customer, Liability, Noncurrent $ 3,100      
Based upon Successful Regulatory and Product Development Efforts [Member]        
Revenue Recognition Milestone Method Agreed, Additional Amount, Based On Efforts And Targets       28,500
Based upon Net Sales Target Achievements [Member]        
Revenue Recognition Milestone Method Agreed, Additional Amount, Based On Efforts And Targets       $ 166,000
[1] The condensed consolidated balance sheet as of December 31, 2018 has been derived from the audited financial statements as of that date included in the Company's Annual Report on Form 10-K for the year ended December 31, 2018.