Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jul. 31, 2017	Jul. 31, 2016
Cash flows from operating activities:
Net loss	$ (82,347)	$ (56,483)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	3,605	4,799
Stock-based compensation expense	25,918	7,441
Accretion of balloon payment	750	402
Amortization of debt issuance cost, credit facility fees and debt discounts	105	221
Other	(13)	(18)
Changes in operating assets and liabilities:
Accounts receivable	11,803	5,662
Inventories	329	(1,009)
Prepaid expenses and other assets	(887)	(2,976)
Payment of offering costs	(1,518)	(1,900)
Accounts payable	(1,583)	2,569
Deferred revenue	4,190	3,540
Accrued and other liabilities	(1,807)	(1,760)
Net cash used in operating activities	(41,455)	(39,512)
Cash flows from investing activities:
Purchase of property and equipment	(2,054)	(2,331)
Purchase of investments	(7,926)	(8,423)
Proceeds from maturities of investments	0	40,810
Net cash provided by (used in) investing activities	(9,980)	30,056
Cash flows from financing activities:
Payment on capital lease financing	(172)	(112)
Proceeds from revolving line of credit	5,000	6,962
Proceeds from term loan	15,000	0
Proceeds from initial public offering, net of underwriting discounts and commissions	55,804	0
Proceeds from repayment of employee notes receivable	0	67
Proceeds from exercise of stock options	470	696
Net cash provided by financing activities	76,102	7,613
Foreign exchange impact on cash and cash equivalents	(24)	(62)
Net increase (decrease) in cash and cash equivalents	24,643	(1,905)
Cash and cash equivalents, beginning of period	48,048	50,716
Cash and cash equivalents, end of period	72,691	48,811
Supplemental disclosures of cash flow information:
Cash paid for income taxes	63	513
Cash paid for interest	3,276	1,906
Supplemental disclosures of noncash investing and financing activities:
Convertible preferred stock warrants issued in connection with debt financing	277	0
Common stock warrants issued to Series E-2 and F-2 Holders	14,641	0
Reclassification of convertible preferred stock warrant liability to additional paid in capital	375	0
Conversion of convertible preferred stock to common stock, net of issuance costs	263,729	0
Offering costs included in accounts payable	2,850	632
Vesting of early exercised options	345	33
Assets acquired through accounts payable	776	563
Vesting of stock options exercised with notes receivable	231	279
Transfer of inventory to sales demonstration equipment	373	174
Transfer of inventory to internal use equipment	105	155
Deemed dividend to series E and E-1 Convertible Preferred Stock	6,588	0
Deemed capital contribution from Series E, E-1 and F Convertible Preferred Stock	26,336	0
Repurchase of common stock by way of note forgiveness	1,211	0
Repayment of executive employee promissory notes through repurchase of common stock	$ 7,899	$ 0