Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Oct. 31, 2017	Oct. 31, 2016
Cash flows from operating activities:
Net loss	$ (89,681)	$ (65,285)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation, amortization and accretion	5,111	3,177
Stock-based compensation	35,292	11,869
Amortization of deferred commissions	12,798	9,926
Deferred income taxes	(960)	0
Non-cash charitable contributions	708	129
Other	997	173
Changes in operating assets and liabilities:
Accounts receivable	(12,742)	(3,606)
Deferred commissions	(12,495)	(11,207)
Prepaid expenses and other current and noncurrent assets	(2,989)	(2,312)
Accounts payable	6,255	2,453
Accrued compensation	5,931	(1,268)
Accrued expenses and other current and noncurrent liabilities	(1,545)	259
Deferred revenue	27,925	20,293
Net cash used in operating activities	(25,395)	(35,399)
Cash flows from investing activities:
Capitalization of internal-use software costs	(4,072)	(3,992)
Purchases of property and equipment and other	(5,570)	(4,647)
Purchases of securities available for sale	(95,344)	0
Proceeds from sales of securities available for sale	1,538	6,207
Proceeds from maturities and redemption of securities available for sale	21,985	5,000
Net cash provided by (used in) investing activities	(81,463)	2,568
Cash flows from financing activities:
Proceeds from initial public offering, net of underwriters' discounts and commissions	199,948	0
Payments of deferred offering costs	(4,038)	(990)
Proceeds from stock option exercises, net of repurchases, and other	25,800	1,665
Principal payments on financing arrangements	(343)	(213)
Net cash provided by financing activities	221,367	462
Effects of changes in foreign currency exchange rates on cash and cash equivalents	53	(144)
Net increase (decrease) in cash, cash equivalents and restricted cash	114,562	(32,513)
Cash, cash equivalents and restricted cash at beginning of period	23,282	58,081
Cash, cash equivalents and restricted cash at end of period	137,844	25,568
Non-cash investing and financing activities:
Vesting of early exercised common stock options	986	997
Issuance of common stock in connection with warrant exercises	272	0
Common stock issued as charitable contribution	708	129
Deferred offering costs, accrued but not yet paid	0	438
Property and equipment and other, accrued but not yet paid	710	990
Issuance of common stock in connection with business combination	2,160	0
Conversion of redeemable convertible preferred stock to common stock	228,362	0
Cash paid for taxes	668	90
Reconciliation of cash, cash equivalents and restricted cash within the condensed consolidated balance sheets to the amounts shown in the statements of cash flows above:
Total cash, cash equivalents and restricted cash	$ 23,282	$ 58,081