Stockholders' Equity - Additional Information (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Jan. 31, 2016 USD ($) Vote $ / shares shares	Oct. 31, 2015 shares	Sep. 30, 2015 shares	Jan. 31, 2015 $ / shares shares
Class Of Stock [Line Items]
Preferred stock, shares authorized	20,000,000	20,000,000		0
Preferred stock, shares issued	0			0
Preferred stock, shares outstanding	0			0
Common stock, shares authorized	2,250,000,000			230,812,000
Common stock, shares issued	190,509,000			36,465,000
Common stock, shares outstanding	190,509,000			36,465,000
Common stock, voting rights	The rights of the holders of Class A and Class B common stock are identical, except with respect to voting. Each share of Class A common stock is entitled to one vote per share. Each share of Class B common stock is entitled to 10 votes per share.
Common stock, conversion features	Shares of Class B common stock may be converted to Class A common stock at any time at the option of the stockholder. Shares of Class B common stock automatically convert to Class A common stock upon the following: (i) sale or transfer of such share of Class B common stock; (ii) the death of the Class B common stockholder (or nine months after the date of death if the stockholder is one of our founders); and (iii) on the final conversion date, defined as the earlier of (a) the first trading day on or after the date on which the outstanding shares of Class B common stock represent less than 10% of the then outstanding Class A and Class B common stock; (b) the tenth anniversary of the IPO; or (c) the date specified by vote of the holders of a majority of the outstanding shares of Class B common stock, voting as a single class.
Class A Common Stock
Class Of Stock [Line Items]
Common stock, shares authorized	2,000,000,000			1,000
Common stock, par value per share | $ / shares	$ 0.0001			$ 0.0001
Common stock, shares issued	28,769,572			0
Common stock, shares outstanding	28,769,572			0
Common stock, entitled votes per share | Vote	1
Class B Common Stock
Class Of Stock [Line Items]
Common stock, shares authorized	250,000,000			230,811,000
Common stock, par value per share | $ / shares	$ 0.0001			$ 0.0001
Common stock, shares issued	161,739,883			36,465,000
Common stock, shares outstanding	161,739,883			36,465,000
Common stock, entitled votes per share | Vote	10
Class B Common Stock | Pure Good Foundation
Class Of Stock [Line Items]
Common stock, shares issued			700,000
Non cash general and administrative expense | $	$ 11.9