Quarterly report pursuant to Section 13 or 15(d)

Stockholders'Equity (Deficit) - Schedule of Common Stock Reserved for Future Issuance (Details)

v3.19.1
Stockholders'Equity (Deficit) - Schedule of Common Stock Reserved for Future Issuance (Details) - shares
Mar. 31, 2019
Dec. 31, 2018
Temporary Equity [Line Items]    
Reserved common stock 7,543,257 6,250,381
Common Stock    
Temporary Equity [Line Items]    
Reserved common stock 3,874,914 3,111,718
Common Stock Awards Issued And Outstanding    
Temporary Equity [Line Items]    
Reserved common stock 464,900 311,240
2004 and 2018 Equity Incentive Plan    
Temporary Equity [Line Items]    
Reserved common stock 2,742,059 2,525,610
2018 Employee Stock Purchase Plan    
Temporary Equity [Line Items]    
Reserved common stock 389,571 230,000
Warrants to Purchase Common Stock    
Temporary Equity [Line Items]    
Reserved common stock 71,813 71,813