Stockholders' Equity - Schedule of Common Stock Reserved for Future Issuance (Detail)	Dec. 31, 2016 shares
Class Of Stock [Line Items]
Total reserved shares of common stock	9,773,461
2014 Equity Incentive Plan
Class Of Stock [Line Items]
Total reserved shares of common stock	9,132,638
2014 Employee Stock Purchase Plan
Class Of Stock [Line Items]
Total reserved shares of common stock	640,823