Fair Value Measurements and Marketable Securities - Unobservable Input Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Adjustment resulting from change in fair value recognized in the consolidated statement of operations		$ 6,000	$ 3,600
Reclassification of redeemable convertible preferred stock warrant liability to additional paid-in capital upon IPO		(10,559)
Shares of common stock issuable upon conversion of redeemable convertible preferred stock warrants \| Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, measurement with unobservable inputs reconciliation, recurring basis, beginning balance	$ 0	4,537	961
Adjustment resulting from change in fair value recognized in the consolidated statement of operations	0	6,022	3,576
Reclassification of redeemable convertible preferred stock warrant liability to additional paid-in capital upon IPO	0	(10,559)	0
Fair value, measurement with unobservable inputs reconciliation, recurring basis,, ending balance	$ 0	$ 0	$ 4,537

Amount of decrease (increase) in additional paid in capital (APIC) for the increase in carrying amount of redeemable preferred stock.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

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- Definition

Amount of gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
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- Definition

Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

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