CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jan. 31, 2018	Jan. 31, 2017
Statement of Financial Position [Abstract]
Allowance for accounts receivable	$ 1,472	$ 1,306
Redeemable convertible preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Redeemable convertible preferred stock, shares authorized (in shares)	0	59,494,582
Redeemable convertible preferred stock, shares issued (in shares)	0	59,465,439
Redeemable convertible preferred stock, shares outstanding (in shares)	0	59,465,439
Redeemable convertible preferred stock, liquidation preference	$ 0	$ 230,373
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	100,000,000	100,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)		$ 0.0001
Common stock, shares authorized (in shares)		120,000,000
Class A Common Stock
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	1,000,000,000	0
Common stock, shares issued (in shares)	70,610,000	0
Common stock, shares outstanding (in shares)	70,609,898	0
Class B Common Stock
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	120,000,000	120,000,000
Common stock, shares issued (in shares)	33,361,000	20,293,000
Common stock, shares outstanding (in shares)	33,361,106	20,229,000