Consolidated Statements of Operations - Parenthetical - USD ($) $ in Thousands	12 Months Ended
Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Amortization expense of intangible assets	$ 80,000	$ 9,100	$ 3,700
Services
Stock-based compensation expense	17,609	11,492	31,843
Subscription
Stock-based compensation expense	16,599	9,959	24,826
Amortization expense of intangible assets	11,213	3,251	2,230
Research and development
Stock-based compensation expense	75,554	41,430	100,143
Sales and marketing
Stock-based compensation expense	63,360	27,918	90,420
Amortization expense of intangible assets	68,811	5,878	1,493
General and administrative
Stock-based compensation expense	$ 47,232	$ 26,566	$ 42,774

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

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