Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Apr. 30, 2020	Apr. 30, 2019
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (58,014)	$ (103,130)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	22,573	23,316
Non-cash lease expense	11,301	11,315
Stock-based compensation expense	53,438	48,871
Amortization of deferred costs	16,625	9,652
Other	3,522	(510)
Changes in assets and liabilities:
Accounts receivable	81,828	95,496
Prepaid expenses and other assets	10,526	(522)
Deferred costs	(10,623)	(9,412)
Accounts payable	307	(2,605)
Accrued compensation	(18,412)	(12,530)
Other accrued liabilities	(2,895)	(28)
Operating lease liabilities	(2,508)	(11,079)
Net cash provided by operating activities	68,357	11,460
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of marketable securities and other investments	(80,860)	(196,453)
Proceeds from sale of marketable securities and other investments	66,059	9,271
Maturities of marketable securities and other investments	36,794	129,998
Capital expenditures	(1,089)	(2,693)
Net cash provided by (used in) investing activities	20,904	(59,877)
CASH FLOWS FROM FINANCING ACTIVITIES
Repurchases of common stock	(25,974)	0
Taxes paid related to net share settlement of restricted stock units	(14,017)	(7,797)
Proceeds from employee stock plans	4,977	5,949
Net cash used in financing activities	(35,014)	(1,848)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(960)	(1,060)
Net increase (decrease) in cash, cash equivalents and restricted cash	53,287	(51,325)
Cash, cash equivalents and restricted cash — Beginning of period	110,990	162,039
Cash, cash equivalents and restricted cash — End of period	164,277	110,714
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES
Purchases of property and equipment, accrued but not yet paid	606	49
Right-of-use assets obtained in exchange for new operating lease liabilities	476	2,429
Reconciliation of cash, cash equivalents and restricted cash as shown in the statement of cash flows
Total cash, cash equivalents and restricted cash	164,277	110,714
Other contract liabilities
Changes in assets and liabilities:
Other contract liabilities / Deferred revenue	(497)	(5,122)
Deferred revenue
Changes in assets and liabilities:
Other contract liabilities / Deferred revenue	$ (38,814)	$ (32,252)