Equity Plans and Stock-based Compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	12 Months Ended
	Feb. 25, 2021	Jun. 30, 2020	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2020
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Total shares of common stock reserved (in shares)			106,331,590	266,494,345
Number of stock options granted (in shares)			0
Unrecognized compensation expense			$ 32,400
2021 Equity Incentive Plan
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Possible increase in percent of outstanding shares (as a percent)	1.00%
Number of additional shares allowable under the plan (in shares)	5,400,000
Percent of outstanding shares (as a percent)	5.00%
2021 Stock Option Plan
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Total shares of common stock reserved (in shares)			36,370,596	0
Number of stock options granted (in shares)			0
2017 Stock Plan
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Total shares of common stock reserved (in shares)			19,071,585
2017 Stock Plan | Chief Executive Officer
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Number of stock options granted (in shares)		1,500,000
Unrecognized compensation expense			$ 28,400	$ 44,300
2007 Stock Plan
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Total shares of common stock reserved (in shares)			3,129,284
Employee stock purchase plan
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Eligible compensation per employee (as a percent)			15.00%
Offering period (in months)			24 months
Purchase period (in months)			6 months
Purchase price of common stock, percent of fair value			85.00%
Maximum number of shares to be purchased per employee (in shares)			10,000
Total shares of common stock reserved (in shares)			8,177,683	0
Share-based compensation cost not yet recognized			$ 6,100
Period for recognition (in years)			1 year 9 months 29 days
Restricted stock units
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Total shares of common stock reserved (in shares)			4,033,418	0
Share-based compensation cost not yet recognized			$ 81,500
Period for recognition (in years)			2 years 9 months 29 days
Granted (in dollars per share)			$ 26.57
Fair value of awards vested			$ 37,800
Stock options issued and outstanding
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Total shares of common stock reserved (in shares)			22,200,869	30,167,178
Period for recognition (in years)			1 year 7 months 17 days
Stock options issued and outstanding | 2017 Stock Plan
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Weighted average grant date fair value (USD per share)			$ 0	$ 0.94	$ 0.31
Grant date fair value			$ 3,400	$ 5,400	$ 2,500
Stock options issued and outstanding | 2017 Stock Plan | Chief Executive Officer
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Period for recognition (in years)			2 years