CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common stock	Additional paid-in capital	Additional paid-in capital Capped Call	Accumulated other comprehensive loss	Accumulated deficit
Cumulative-effect adjustment from adoption of ASU | Accounting Standards Update 2016-02						$ 7,241
Balance, beginning of period at Jan. 31, 2019		$ 149	$ 2,754,858		$ (2,506)	(1,232,044)
Issuance of restricted stock awards		1
Vesting of restricted stock units		2
Issuance of common stock		3
Issuance of common stock upon ESPP purchase		0
Stock-based compensation			378,928
Capitalized software development costs			0
Issuance of common stock upon exercise of options			$ 622
Issuance of common stock from acquisitions			344,569
Fair value of replacement equity awards attributable to pre-acquisition service			$ 18,567
Vesting of early exercised options	$ 0		0
Taxes paid related to net share settlement of equity awards			(164,160)
Issuance of common stock upon ESPP purchase			34,482
Equity component of convertible senior notes, net			0
Purchase of capped calls				$ 0
Partial repurchase of convertible senior notes			0
Unrealized gain (loss) from investments (net of tax)					2,044
Net change in cumulative translation adjustments	(2,699)				(2,699)
Net loss	(313,940)					(313,940)
Balance, end of period at Oct. 31, 2019	1,826,117	155	3,367,866		(3,161)	(1,538,743)
Cumulative-effect adjustment from adoption of ASU | Accounting Standards Update 2016-02						0
Balance, beginning of period at Jul. 31, 2019		151	2,918,277		(3,484)	(1,481,104)
Issuance of restricted stock awards		1
Vesting of restricted stock units		0
Issuance of common stock		3
Issuance of common stock upon ESPP purchase		0
Stock-based compensation			132,852
Capitalized software development costs			0
Issuance of common stock upon exercise of options			$ 68
Issuance of common stock from acquisitions			344,569
Fair value of replacement equity awards attributable to pre-acquisition service			$ 18,567
Vesting of early exercised options			0
Taxes paid related to net share settlement of equity awards			(46,467)
Issuance of common stock upon ESPP purchase			0
Equity component of convertible senior notes, net			0
Purchase of capped calls				0
Partial repurchase of convertible senior notes			0
Unrealized gain (loss) from investments (net of tax)					1,002
Net change in cumulative translation adjustments	(679)				(679)
Net loss	(57,639)					(57,639)
Balance, end of period at Oct. 31, 2019	1,826,117	155	3,367,866		(3,161)	(1,538,743)
Cumulative-effect adjustment from adoption of ASU | Accounting Standards Update 2016-02						0
Balance, beginning of period at Jan. 31, 2020	1,999,429	157	3,566,055		(5,312)	(1,561,471)
Issuance of restricted stock awards		0
Vesting of restricted stock units		4
Issuance of common stock		0
Issuance of common stock upon ESPP purchase		1
Stock-based compensation			452,481
Capitalized software development costs			5,862
Issuance of common stock upon exercise of options			$ 3,083
Issuance of common stock from acquisitions			0
Fair value of replacement equity awards attributable to pre-acquisition service			$ 0
Vesting of early exercised options	164		164
Taxes paid related to net share settlement of equity awards			(49,235)
Issuance of common stock upon ESPP purchase			44,214
Equity component of convertible senior notes, net			342,062
Purchase of capped calls				(137,379)
Partial repurchase of convertible senior notes			(283,629)
Unrealized gain (loss) from investments (net of tax)					(407)
Net change in cumulative translation adjustments	1,094				1,094
Net loss	(768,432)					(768,432)
Balance, end of period at Oct. 31, 2020	1,609,312	162	3,943,678		(4,625)	(2,329,903)
Cumulative-effect adjustment from adoption of ASU | Accounting Standards Update 2016-02						0
Balance, beginning of period at Jul. 31, 2020		160	3,802,423		(4,730)	(2,128,372)
Issuance of restricted stock awards		0
Vesting of restricted stock units		2
Issuance of common stock		0
Issuance of common stock upon ESPP purchase		0
Stock-based compensation			138,790
Capitalized software development costs			2,012
Issuance of common stock upon exercise of options			$ 413
Issuance of common stock from acquisitions			0
Fair value of replacement equity awards attributable to pre-acquisition service			$ 0
Vesting of early exercised options			47
Taxes paid related to net share settlement of equity awards			(7)
Issuance of common stock upon ESPP purchase			0
Equity component of convertible senior notes, net			0
Purchase of capped calls				$ 0
Partial repurchase of convertible senior notes			0
Unrealized gain (loss) from investments (net of tax)					(1,093)
Net change in cumulative translation adjustments	1,198				1,198
Net loss	(201,531)					(201,531)
Balance, end of period at Oct. 31, 2020	$ 1,609,312	$ 162	$ 3,943,678		$ (4,625)	$ (2,329,903)