Quarterly report pursuant to Section 13 or 15(d)

Nature of Business (Details)

v3.19.2
Nature of Business (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended 12 Months Ended
Apr. 09, 2019
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]                
Net Loss   $ 19,455 $ 14,047 $ 35,916 $ 28,510 $ 62,300 $ 54,000 $ 47,700
Accumulated deficit   (253,461)   (253,461)   $ (217,545)    
Cash equivalents and marketable securities   $ 121,700   $ 121,700        
Gross proceeds from public offerings $ 70,000