XML 43 R29.htm IDEA: XBRL DOCUMENT v3.10.0.1
Description of Business - Narrative (Details) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 3 Months Ended 6 Months Ended 16 Months Ended
Feb. 13, 2017
Aug. 31, 2018
Feb. 28, 2018
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Dec. 31, 2017
Mar. 31, 2017
Dec. 31, 2016
Description of Business [Line Items]                      
Accumulated deficit       $ (106,968)   $ (106,968)   $ (106,968) $ (93,593)    
Net loss       $ (8,714) $ (7,312) (13,375) $ (14,292)        
Proceeds from the sale of common stock $ 40,700         $ 2,700   10,200      
Aggregate offering price               $ 50,000      
Shares sold (in shares)           372,852   1,213,386      
Common stock, par value (in dollars per share)       $ 0.01   $ 0.01   $ 0.01 $ 0.01    
Weighted-average share price (in usd per share)           $ 7.37   $ 8.74      
Cash and cash equivalents       $ 43,402   $ 43,402   $ 43,402 $ 47,441 $ 46,335 $ 22,104
Short-term investments       $ 32,860   $ 32,860   $ 32,860 $ 0    
Underwriting Agreement                      
Description of Business [Line Items]                      
Sale price (in usd per share)     $ 5.50                
Underwriter Option                      
Description of Business [Line Items]                      
Proceeds from the sale of common stock     $ 37,900                
Shares sold (in shares)     7,414,996                
Subsequent Event | LLS                      
Description of Business [Line Items]                      
Aggregate offering price   $ 5,000                  
Shares sold (in shares)   150,987                  
Sale price (in usd per share)   $ 6.62