Annual report pursuant to Section 13 and 15(d)

Organization and Description of the Business (Details)

v3.20.1
Organization and Description of the Business (Details)
$ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2019
USD ($)
Sep. 30, 2019
USD ($)
Jun. 30, 2019
USD ($)
Mar. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Sep. 30, 2018
USD ($)
Jun. 30, 2018
USD ($)
Mar. 31, 2018
USD ($)
Dec. 31, 2019
USD ($)
segment
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Organization and Description of the Business                      
Number of operating segments | segment                 1    
Accumulated deficit $ 413,145       $ 388,274       $ 413,145 $ 388,274  
Net loss 6,445 $ 8,566 $ 4,691 $ 5,169 7,976 $ 4,483 $ 9,304 $ 9,021 24,871 30,784 $ 71,865
Cash and cash equivalents 32,305       32,892       32,305 32,892  
Marketable securities $ 3,500       $ 28,590       $ 3,500 $ 28,590