Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (336,582)	$ (192,649)	$ (369,672)
Other comprehensive income, net of tax:
Foreign currency translation (loss) gain	(935)	34	349
Unrealized gain (loss) on investments	1,250	756	(625)
Total other comprehensive income (loss), net of tax	315	790	(276)
Comprehensive loss	$ (336,267)	$ (191,859)	$ (369,948)

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature, attributable to parent entity.

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Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities.

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