XML 53 R32.htm IDEA: XBRL DOCUMENT v3.19.3
Stockholder’s equity (deficit) - Undesignated preferred stock and Restricted common stock (Details) - $ / shares
1 Months Ended 3 Months Ended 9 Months Ended
Jul. 31, 2019
Jun. 30, 2019
Apr. 30, 2019
Oct. 31, 2017
Mar. 31, 2017
Sep. 30, 2019
Jun. 30, 2019
Sep. 30, 2019
Common Stock                
Class of Stock                
Issuance of restricted common stock upon early exercise of stock options (in shares) 491,207 491,207 491,207     3,274 487,933 383,320
Restricted stock                
Class of Stock                
Shares issued (in shares)         226,400      
Stock options vesting period       2 years 4 years      
Number of shares subject to be repurchased       75,467        
Undesignated Preferred Stock                
Class of Stock                
Preferred stock, par value (in dollars per share)           $ 0.0001   $ 0.0001
Preferred stock, Shares Issued           0   0
Preferred stock, Shares Outstanding           0   0
Undesignated Preferred Stock | Maximum                
Class of Stock                
Preferred stock, shares authorized           10,000,000   10,000,000