CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (154,960)	$ (151,787)	$ (202,948)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	40,112	40,154	40,394
Stock-based compensation expense	97,485	78,372	59,504
Amortization of deferred commissions	21,476	18,260	15,816
Other	(101)	114	1,089
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable, net	(42,020)	(20,571)	(45,368)
Deferred commissions	(26,133)	(20,047)	(21,725)
Prepaid expenses, restricted cash and other assets, current and noncurrent	23,990	5,858	(25,717)
Accounts payable	6,900	(1,093)	(4,022)
Accrued expenses and other liabilities	12,930	(9,035)	17,943
Deferred rent	3,204	2,986	32,357
Deferred revenue	78,939	55,571	66,356
Net cash provided by (used in) operating activities	61,822	(1,218)	(66,321)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of marketable securities			(112,521)
Sales of marketable securities		240	78,427
Maturities of marketable securities		7,057	26,370
Purchases of property and equipment	(11,822)	(14,956)	(72,939)
Proceeds from sale of property and equipment	107	87	73
Acquisitions and purchases of intangible assets, net of cash acquired			(271)
Net cash used in investing activities	(11,715)	(7,572)	(80,861)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from initial public offering, net of offering costs			(2,172)
Proceeds from borrowings, net of borrowing costs	39,930	(106)	39,860
Principal payments on borrowings	(40,000)		(40,000)
Proceeds from exercise of stock options, net of repurchases of early exercised stock options	14,538	11,086	7,015
Proceeds from issuances of common stock under employee stock purchase plan	17,521	15,726	10,282
Employee payroll taxes paid related to net share settlement of restricted stock units	(34,776)	(17,552)	(10,436)
Payments of capital lease obligations	(16,052)	(8,675)	(2,036)
Acquisition related contingent consideration	(991)
Net cash (used in) provided by financing activities	(19,830)	479	2,513
Effect of exchange rate changes on cash and cash equivalents	408	(39)	(26)
Net increase (decrease) in cash and cash equivalents	30,685	(8,350)	(144,695)
Cash and cash equivalents, beginning of period	177,391	185,741	330,436
Cash and cash equivalents, end of period	208,076	177,391	185,741
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for interest, net of amounts capitalized	1,936	1,235	1,183
Cash paid for income taxes, net of tax refunds	1,259	239	832
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Change in accrued equipment purchases	4,983	(14,781)	10,766
Purchases of property and equipment under capital lease	26,431	31,849	13,138
Change in unpaid tax related to capital lease	$ 753	1,521
Issuance of common stock in connection with acquisitions and purchases of intangible assets		1,011	6,108
Vesting of early exercised stock options and restricted stock		$ 10	127
Change in unpaid deferred offering costs			$ (2,172)