Equity - Narrative (Details) $ / shares in Units, $ in Thousands				1 Months Ended				2 Months Ended	3 Months Ended			6 Months Ended		13 Months Ended
	Mar. 01, 2021 vote $ / shares shares	Feb. 28, 2021 vote	Feb. 28, 2020	Sep. 30, 2020 USD ($) $ / shares shares	Mar. 31, 2020 shares	Mar. 31, 2019 USD ($) shares	Dec. 31, 2017 $ / shares shares	Jun. 30, 2020 USD ($)	Jul. 31, 2021 USD ($) class $ / shares shares	Apr. 30, 2021 shares	Jul. 31, 2020 USD ($)	Jul. 31, 2021 USD ($) class $ / shares shares	Jul. 31, 2020 USD ($) $ / shares	Apr. 30, 2020 USD ($)	Jan. 31, 2021 USD ($) $ / shares shares	Feb. 29, 2020 $ / shares
Share-based Compensation Arrangement by Share-based Payment Award
Preferred stock, shares authorized (in shares)				200,000,000					200,000,000			200,000,000			200,000,000
Preferred stock, par value (in dollars per share) | $ / shares				$ 0.0001					$ 0.0001			$ 0.0001			$ 0.0001
Common stock, number of classes of stock | class									2			2
Conversion, percent threshold			10.00%
Common stock reserved for future issuances (shares)									117,102,337			117,102,337			112,494,580
Options granted (shares)												0
Granted (in dollars per share) | $ / shares													$ 17.01
Intrinsic value of shares exercised | $												$ 2,600,000	$ 293,300
Grant date fair value of vested shares | $												44,100	50,800
Proceeds from repayments of a nonrecourse promissory note | $												0	2,090
Share-based compensation | $									$ 163,991		$ 18,204	$ 315,005	38,649
Shares subject to repurchase (in shares)									114,569			114,569			245,633
Liabilities for common stock subject to repurchase | $									$ 700			$ 700			$ 1,200
Compensation modification cost | $													$ 2,700	$ 16,700
Unrecognized share-based compensation expense | $									$ 1,500,000			$ 1,500,000
Unrecognized share-based compensation expense recognition period (term)												3 years 1 month 6 days
Employee stock purchase rights under the 2020 ESPP
Share-based Compensation Arrangement by Share-based Payment Award
Common stock reserved for future issuances (shares)									8,320,369			8,320,369			5,700,000
Stock market discount												85.00%
Offering period												6 months
Stock options
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period (years)												4 years
Expiration period (years)												10 years
RSUs
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period (years)												4 years
Unvested shares (shares)									10,763,236	11,117,993		10,763,236			9,348,557
Vested (shares)									820,002	531,845
Share-based compensation | $				$ 55,500
2020 Plan | RSUs
Share-based Compensation Arrangement by Share-based Payment Award
Common stock reserved for future issuances (shares)									4,680,406			4,680,406			1,828,083
2012 Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award
Common stock reserved for future issuances (shares)									52,250,088			52,250,088			64,574,656
Expiration period (years)												10 years
2012 Plan | RSUs
Share-based Compensation Arrangement by Share-based Payment Award
Common stock reserved for future issuances (shares)									6,082,830			6,082,830			7,520,474
Out of the Plans | RSA
Share-based Compensation Arrangement by Share-based Payment Award
Unvested shares (shares)									561,085	651,499		561,085			741,911
Vested (shares)									90,414	90,412
Out of the Plans | RSA | Privately-Held Company
Share-based Compensation Arrangement by Share-based Payment Award
Unvested shares (shares)									186,085			186,085
Issuance of common stock in connection with an acquisition (in shares)						661,635
Vested (shares)						215,031
Share-based compensation | $						$ 1,100
Vesting period (years)						4 years
Out of the Plans | RSA | Privately-Held Company | Share-based Payment Arrangement, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period (years)						4 years
Out of the Plans | RSA | Promissory Notes
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period (years)							5 years
Shares authorized (shares)							1,250,000
Shares issued (in dollars per share) | $ / shares							$ 1.59
Debt instrument, stated interest rate							2.11%
Proceeds from repayments of a nonrecourse promissory note | $								$ 2,100
Unvested shares (shares)									375,000			375,000
Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award
Common stock, shares authorized (in shares)				2,500,000,000					2,500,000,000			2,500,000,000			2,500,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001								$ 0.0001			$ 0.0001			$ 0.0001
Common stock, voting rights, votes per share | vote	1
Class A Common Stock | Employee stock purchase rights under the 2020 ESPP
Share-based Compensation Arrangement by Share-based Payment Award
Common stock reserved for future issuances (shares)				5,700,000
Class A Common Stock | 2020 Plan
Share-based Compensation Arrangement by Share-based Payment Award
Common stock reserved for future issuances (shares)				34,100,000
Maximum common shares authorized to be outstanding (shares)				78,816,888
Class B Common Stock
Share-based Compensation Arrangement by Share-based Payment Award
Common stock, shares authorized (in shares)				355,000,000					185,461,432			185,461,432			355,000,000
Shares converted (in shares)	169,538,568
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001								$ 0.0001			$ 0.0001			$ 0.0001
Common stock, voting rights, votes per share | vote		10
Shares issued (in dollars per share) | $ / shares																$ 38.77
Shares issued for common stock (shares)					8,600,000