Adjustment to additional paid in capital resulting from the recognition of convertible debt instruments as two separate components - a debt component and an equity component. This bifurcation may result in a basis difference associated with the liability component that represents a temporary difference for purposes of applying accounting for income taxes. The initial recognition of deferred taxes for the tax effect of that temporary difference is as an adjustment to additional paid in capital.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 25
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=51819886&loc=SL6014347-161799

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance, shares at Jan. 31, 2016		194,479,350
Balance at Jan. 31, 2016	$ 1,226,280	$ 193	$ 2,247,454		$ 799	$ (1,022,166)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee equity plans (in shares)		4,379,787
Issuance of common stock under employee equity plans	58,079	$ 4	58,075
Vesting of early exercised stock options	1,803	$ 1
Vesting of early exercised stock options	1,803		1,802
Vested restricted stock units (in shares)		4,084,268
Vested restricted stock units	0	$ 4
Vested restricted stock units			(4)
Share-based compensation	372,272		372,272
Excess tax benefits from share-based compensation	1,226		1,226
Other	375		375
Other comprehensive income (loss)	1,272				1,272
Net loss	(384,699)					(384,699)
Balance, shares at Jan. 31, 2017		202,943,405
Balance at Jan. 31, 2017	1,276,608	$ 202	2,681,200		2,071	(1,406,865)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee equity plans (in shares)		3,318,514
Issuance of common stock under employee equity plans	69,055	$ 3	69,052
Vesting of early exercised stock options			775
Vesting of early exercised stock options	775
Vested restricted stock units (in shares)		5,715,576
Vested restricted stock units	0	$ 6
Vested restricted stock units			(6)
Share-based compensation	478,425		478,425
Purchase of convertible senior notes hedges	(175,530)		(175,530)
Adjustments to Additional Paid in Capital, Warrant Issued			80,805
Issuance of warrants	80,805
Equity component of convertible senior notes	219,702		219,702
Other comprehensive income (loss)	(48,484)				(48,484)
Net loss	(321,222)					(321,222)
Balance, shares at Jan. 31, 2018		211,977,495
Balance at Jan. 31, 2018	1,580,365	$ 211	3,354,423		(46,413)	(1,727,856)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee equity plans (in shares)		2,317,463
Issuance of common stock under employee equity plans	93,567	$ 2	37,752	$ 55,813
Vesting of early exercised stock options	0
Vested restricted stock units (in shares)		6,273,733
Vested restricted stock units	0	$ 6
Vested restricted stock units			(6)
Share-based compensation	652,404		652,404
Exercise of convertible senior notes hedges	1		193,680	(193,679)
Settlement of warrants (in shares)		25,990
Settlement of warrants	(13)		(137,245)	137,849		(617)
Settlement of convertible senior notes (in shares)		1,457,382
Settlement of convertible senior notes	(5)	$ 2	(24)	$ 17
Equity awards assumed in business combination	4,350		4,350
Other comprehensive income (loss)	45,604				45,604
Net loss	(418,258)					(418,258)
Balance, shares at Jan. 31, 2019		222,052,063
Balance at Jan. 31, 2019	$ 1,958,442	$ 221	$ 4,105,334		$ (809)	$ (2,146,304)