Common Stock - Schedule of Common Share Reserved for Future Issuance (Details) - shares	Sep. 30, 2019	Dec. 31, 2018
Class Of Stock [Line Items]
Common stock, capital shares reserved for future issuance	20,064,951
Shares available for future stock option grants	8,582,012	7,255,050
Options Issued and Outstanding
Class Of Stock [Line Items]
Common stock, capital shares reserved for future issuance	10,439,076
Restricted Stock Units (RSUs)
Class Of Stock [Line Items]
Common stock, capital shares reserved for future issuance	995,381
Common Stock Warrants
Class Of Stock [Line Items]
Common stock, capital shares reserved for future issuance	48,482