Stockholders' Equity - Summary of Common Stock Reserved for Future Issuance (Detail)	Dec. 31, 2016 shares
Class Of Stock [Line Items]
Common stock reserved for future issuance	135,024,000
2013 Equity incentive plan
Class Of Stock [Line Items]
Outstanding options and restricted stock unit awards	10,938,000
Available for future grants	8,702,558
2013 Employee stock purchase plan
Class Of Stock [Line Items]
Common stock reserved for future issuance	2,292,000
Available for future grants	2,291,580
Class B common stock
Class Of Stock [Line Items]
Common stock reserved for future issuance	13,091,000
Preferred Stock
Class Of Stock [Line Items]
Common stock reserved for future issuance	100,000,000