Condensed Consolidated Statements of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Stock-based compensation		$ 28,370	$ 19,718	$ 49,126	$ 36,729
Subscription services
Revenues		266,900	209,609	511,652	405,156
Cost of revenues:
Cost of revenues	[1]	70,218	59,226	135,721	119,381
Gross profit		196,682	150,383	375,931	285,775
Operating expenses:
Research and development	[1]	51,146	38,826	96,119	76,023
Sales and marketing	[1]	45,821	38,222	85,438	72,607
General and administrative	[1]	25,859	20,517	49,349	40,371
Total operating expenses	[1]	122,826	97,565	230,906	189,001
Operating income		73,856	52,818	145,025	96,774
Other income, net		7,332	3,342	13,493	5,481
Income before income taxes		81,188	56,160	158,518	102,255
Provision for income taxes		1,946	5,874	5,827	7,659
Net income		79,242	50,286	152,691	94,596
Net income attributable to Class A and Class B common stockholders, basic and diluted		$ 79,242	$ 50,286	$ 152,691	$ 94,596
Net income per share attributable to Class A and Class B common stockholders:
Basic (in usd per share)		$ 0.54	$ 0.35	$ 1.04	$ 0.66
Diluted (in usd per share)		$ 0.50	$ 0.32	$ 0.96	$ 0.61
Weighted-average shares used to compute net income per share attributable to Class A and Class B common stockholders:
Basic (in shares)		147,510	143,748	147,116	143,271
Diluted (in shares)		158,675	155,416	158,339	155,227
Other comprehensive income:
Net change in unrealized gain on available-for-sale investments		$ 461	$ 357	$ 1,423	$ 662
Net change in cumulative foreign currency translation loss		(1,742)	(1,572)	(2,444)	(2,381)
Comprehensive income		77,961	49,071	151,670	92,877
Subscription services
Subscription services
Revenues		217,312	169,592	415,427	325,595
Cost of revenues:
Cost of revenues	[1]	31,480	29,146	61,858	59,059
Professional services and other
Subscription services
Revenues		49,588	40,017	96,225	79,561
Cost of revenues:
Cost of revenues	[1]	38,738	30,080	73,863	60,322
Cost of subscription services
Stock-based compensation		583	416	968	761
Cost of professional services and other
Stock-based compensation		4,458	2,657	7,436	4,985
Research and development
Stock-based compensation		9,509	5,795	15,833	10,462
Sales and marketing
Stock-based compensation		7,177	4,830	12,325	8,918
General and administrative
Stock-based compensation		$ 6,643	$ 6,020	$ 12,564	$ 11,603

[1] Includes stock-based compensation as follows: Cost of revenues:               Cost of subscription services $ 583
  $ 416
  $ 968
  $ 761
Cost of professional services and other 4,458
  2,657
  7,436
  4,985
Research and development 9,509
  5,795
  15,833
  10,462
Sales and marketing 7,177
  4,830
  12,325
  8,918
General and administrative 6,643
  6,020
  12,564
  11,603
Total stock-based compensation $ 28,370
  $ 19,718
  $ 49,126
  $ 36,729