Net Income Per Share Attributable to Common Stockholders - Schedule of Computation of Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Numerator:
Net income	$ 198,642	$ 2,211	$ 411,706	$ 9,966
Net income attributable to common stockholders	$ 198,440	$ 2,207	$ 411,175	$ 7,473
Denominator:
Weighted-average shares used in computing net income per share attributable to common stockholders, basic (in shares)	284,783,006	273,316,850	282,564,481	219,295,445
Weighted-average shares used in computing net income per share attributable to common stockholders, diluted (in shares)	299,258,765	292,771,122	297,605,941	241,512,569
Net income per share attributable to common stockholders, basic (in dollars per share)	$ 0.70	$ 0.01	$ 1.46	$ 0.03
Net income per share attributable to common stockholders, diluted (in dollars per share)	$ 0.66	$ 0.01	$ 1.38	$ 0.03
Other comprehensive income (loss)	$ (1,455)	$ 719	$ 508	$ 786
Class A Common Stock
Numerator:
Net income	136,849	580	256,176	1,337
Less: undistributed earnings attributable to participating securities	0	0	0	0
Net income attributable to common stockholders	136,849	580	256,176	1,337
Reallocation of net income attributable to common stockholders	(4,094)	(36)	(9,083)	(121)
Net income (loss) attributable to common stockholders, diluted	$ 132,755	$ 544	$ 247,093	$ 1,216
Denominator:
Weighted-average shares used in computing net income per share attributable to common stockholders, basic (in shares)	196,393,625	71,833,141	176,047,037	39,227,409
Weighted-average shares used in computing net income per share attributable to common stockholders, diluted (in shares)	200,202,338	72,117,530	178,844,073	39,294,822
Net income per share attributable to common stockholders, basic (in dollars per share)	$ 0.70	$ 0.01	$ 1.46	$ 0.03
Net income per share attributable to common stockholders, diluted (in dollars per share)	$ 0.66	$ 0.01	$ 1.38	$ 0.03
Class B Common Stock
Numerator:
Net income	$ 61,793	$ 1,631	$ 155,530	$ 8,629
Less: undistributed earnings attributable to participating securities	(202)	(4)	(531)	(2,493)
Net income attributable to common stockholders	61,591	1,627	154,999	6,136
Reallocation of net income attributable to common stockholders	4,094	36	9,083	121
Net income (loss) attributable to common stockholders, diluted	$ 65,685	$ 1,663	$ 164,082	$ 6,257
Denominator:
Weighted-average shares used in computing net income per share attributable to common stockholders, basic (in shares)	88,389,381	201,483,709	106,517,444	180,068,036
Weighted-average shares used in computing net income per share attributable to common stockholders, diluted (in shares)	99,056,427	220,653,592	118,761,868	202,217,747
Net income per share attributable to common stockholders, basic (in dollars per share)	$ 0.70	$ 0.01	$ 1.46	$ 0.03
Net income per share attributable to common stockholders, diluted (in dollars per share)	$ 0.66	$ 0.01	$ 1.38	$ 0.03