Quarterly report pursuant to Section 13 or 15(d)

Organization and Description of the Business (Details)

v3.19.3
Organization and Description of the Business (Details) - USD ($)
3 Months Ended 9 Months Ended
Sep. 30, 2019
Jun. 30, 2019
Mar. 31, 2019
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Sep. 30, 2019
Sep. 30, 2018
Dec. 31, 2018
Organization and Description of the Business                  
Number of operating segments             1    
Accumulated deficit $ (406,700,000)           $ (406,700,000)   $ (388,274,000)
Net loss (8,566,000) $ (4,691,000) $ (5,169,000) $ (4,483,000) $ (9,304,000) $ (9,021,000) (18,426,000) $ (22,808,000)  
Cash and cash equivalents 29,255,000           29,255,000   32,892,000
Marketable securities $ 15,461,000           $ 15,461,000   $ 28,590,000