Condensed Consolidated Statements of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands		3 Months Ended			6 Months Ended
		Jul. 31, 2018	Jul. 31, 2017	[1]	Jul. 31, 2018	Jul. 31, 2017	[1]
Revenues:
Revenues		$ 209,609	$ 167,795		$ 405,156	$ 327,567
Cost of revenues:
Cost of revenues	[2]	59,226	50,400		119,381	99,277
Gross profit		150,383	117,395		285,775	228,290
Operating expenses:
Research and development	[2]	38,826	32,678		76,023	60,989
Sales and marketing	[2]	38,222	32,070		72,607	62,211
General and administrative	[2]	20,517	14,580		40,371	28,160
Total operating expenses	[2]	97,565	79,328		189,001	151,360
Operating income		52,818	38,067		96,774	76,930
Other income, net		3,342	2,858		5,481	3,449
Income before income taxes		56,160	40,925		102,255	80,379
Provision for income taxes		5,874	2,323		7,659	4,781
Net income		50,286	38,602		94,596	75,598
Net income attributable to Class A and Class B common stockholders, basic and diluted		$ 50,286	$ 38,602		$ 94,596	$ 75,598
Net income per share attributable to Class A and Class B common stockholders:
Basic		$ 0.35	$ 0.28		$ 0.66	$ 0.54
Diluted		$ 0.32	$ 0.25		$ 0.61	$ 0.49
Weighted-average shares used to compute net income per share attributable to Class A and Class B common stockholders:
Basic		143,748	140,010		143,271	139,351
Diluted		155,416	153,778		155,227	153,301
Other comprehensive income:
Net change in unrealized losses on available-for-sale investments		$ 357	$ 34		$ 662	$ (72)
Net change in cumulative foreign currency translation gain (loss)		(1,572)	327		(2,381)	1,232
Comprehensive income		49,071	38,963		92,877	76,758
Subscription services [Member]
Revenues:
Revenues		169,592	135,550		325,595	264,681
Cost of revenues:
Cost of revenues	[2]	29,146	26,800		59,059	52,938
Professional services and other [Member]
Revenues:
Revenues		40,017	32,245		79,561	62,886
Cost of revenues:
Cost of revenues	[2]	$ 30,080	$ 23,600		$ 60,322	$ 46,339

[1] See note 1 of the notes to the condensed consolidated financial statements for a summary of adjustments.

[2] Includes stock-based compensation as follows:  Cost of revenues: Cost of subscription services $416 $376 $761 $718 Cost of professional services and other 2,657 2,133 4,985 3,822 Research and development 5,795 4,349 10,462 8,151 Sales and marketing 4,830 4,173 8,918 8,020 General and administrative 6,020 2,349 11,603 4,457 Total stock-based compensation $19,718 $13,380 $36,729 $25,168