CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Apr. 30, 2017	Apr. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (40,086)	$ (38,575)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	9,572	12,084
Stock-based compensation expense	22,946	16,089
Amortization of deferred commissions	4,990	4,771
Other	22	108
Changes in operating assets and liabilities:
Accounts receivable, net	37,346	41,927
Deferred commissions	(2,784)	(2,257)
Prepaid expenses and other assets, current and noncurrent	(2,541)	(227)
Accounts payable	7,182	266
Accrued expenses and other liabilities	(10,967)	(26,698)
Deferred rent	530	2,510
Deferred revenue	(17,669)	(14,229)
Net cash provided by (used in) operating activities	8,541	(4,231)
CASH FLOWS FROM INVESTING ACTIVITIES:
Maturities of marketable securities		6,586
Purchases of property and equipment	(784)	(10,976)
Proceeds from sale of property and equipment	27	4
Net cash used in investing activities	(757)	(4,386)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment of borrowing costs		(93)
Proceeds from exercise of stock options, net of repurchases of early exercised stock options	2,456	2,246
Proceeds from issuances of common stock under employee stock purchase plan	8,881	9,016
Employee payroll taxes paid related to net share settlement of restricted stock units	(9,114)	(4,768)
Payments of capital lease obligations	(3,736)	(949)
Net cash (used in) provided by financing activities	(1,513)	5,452
Effect of exchange rate changes on cash and cash equivalents	29	114
Net increase (decrease) in cash and cash equivalents	6,300	(3,051)
Cash and cash equivalents, beginning of period	177,391	185,741
Cash and cash equivalents, end of period	183,691	182,690
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for interest, net of amounts capitalized	423	233
Cash paid for income taxes, net of tax refunds	545	118
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Change in accrued equipment purchases	(1,164)	(12,844)
Purchases of property and equipment under capital lease	9,709	4,348
Change in unpaid tax related to capital lease	$ 235	(198)
Change in unpaid taxes related to net share settlement of restricted stocks		461
Vesting of early exercised stock options and restricted stock		$ 11