Condensed Consolidated Statements of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Stock-based compensation		$ 29,321	$ 19,918	$ 78,447	$ 56,647
Subscription services
Revenues		280,921	224,731	792,573	629,887
Cost of revenues:
Cost of revenues	[1]	73,329	61,374	209,050	180,755
Gross profit		207,592	163,357	583,523	449,132
Operating expenses:
Research and development	[1]	52,575	40,001	148,694	116,024
Sales and marketing	[1]	45,524	37,699	130,962	110,306
General and administrative	[1]	28,693	22,563	78,042	62,934
Total operating expenses	[1]	126,792	100,263	357,698	289,264
Operating income		80,800	63,094	225,825	159,868
Other income, net		9,141	4,606	22,634	10,087
Income before income taxes		89,941	67,700	248,459	169,955
Provision for income taxes		7,696	3,615	13,523	11,274
Net income		82,245	64,085	234,936	158,681
Net income, basic and diluted		$ 82,245	$ 64,085	$ 234,936	$ 158,681
Net income per share:
Basic (in usd per share)		$ 0.56	$ 0.44	$ 1.59	$ 1.10
Diluted (in usd per share)		$ 0.52	$ 0.41	$ 1.49	$ 1.02
Weighted-average shares used to compute net income per share:
Basic (in shares)		148,157	144,737	147,467	143,765
Diluted (in shares)		158,750	156,025	158,124	155,706
Other comprehensive income:
Net change in unrealized gain on available-for-sale investments		$ 753	$ 33	$ 2,176	$ 695
Net change in cumulative foreign currency translation loss		(487)	(1,153)	(2,931)	(3,534)
Comprehensive income		82,511	62,965	234,181	155,842
Subscription services
Subscription services
Revenues		226,760	178,214	642,187	503,809
Cost of revenues:
Cost of revenues	[1]	31,964	28,335	93,822	87,394
Professional services and other
Subscription services
Revenues		54,161	46,517	150,386	126,078
Cost of revenues:
Cost of revenues	[1]	41,365	33,039	115,228	93,361
Cost of subscription services
Stock-based compensation		560	405	1,528	1,166
Cost of professional services and other
Stock-based compensation		4,825	2,782	12,261	7,767
Research and development
Stock-based compensation		9,899	5,820	25,732	16,282
Sales and marketing
Stock-based compensation		6,882	4,825	19,207	13,743
General and administrative
Stock-based compensation		$ 7,155	$ 6,086	$ 19,719	$ 17,689

[1] Includes stock-based compensation as follows: Cost of revenues:               Cost of subscription services $ 560
  $ 405
  $ 1,528
  $ 1,166
Cost of professional services and other 4,825
  2,782
  12,261
  7,767
Research and development 9,899
  5,820
  25,732
  16,282
Sales and marketing 6,882
  4,825
  19,207
  13,743
General and administrative 7,155
  6,086
  19,719
  17,689
Total stock-based compensation $ 29,321
  $ 19,918
  $ 78,447
  $ 56,647