CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Class A & B common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income
Beginning balance (in shares) at Jan. 31, 2020		149,095,583
Beginning balance at Jan. 31, 2020	$ 1,665,594	$ 1	$ 745,475	$ 919,658	$ 460
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)		1,106,371
Issuance of common stock upon exercise of stock options	19,029	$ 1	19,028
Issuance of common stock upon vesting of restricted stock units (in shares)		537,896
Stock-based compensation expense	86,273		86,273
Change in other comprehensive income (loss)	5,710				5,710
Net income	180,121			180,121
Ending balance (in shares) at Jul. 31, 2020		150,739,850
Ending balance at Jul. 31, 2020	1,956,727	$ 2	850,776	1,099,779	6,170
Beginning balance (in shares) at Apr. 30, 2020		150,030,047
Beginning balance at Apr. 30, 2020	1,801,036	$ 2	792,660	1,006,228	2,146
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)		460,856
Issuance of common stock upon exercise of stock options	8,750		8,750
Issuance of common stock upon vesting of restricted stock units (in shares)		248,947
Stock-based compensation expense	49,366		49,366
Change in other comprehensive income (loss)	4,024				4,024
Net income	93,551			93,551
Ending balance (in shares) at Jul. 31, 2020		150,739,850
Ending balance at Jul. 31, 2020	1,956,727	$ 2	850,776	1,099,779	6,170
Beginning balance (in shares) at Jan. 31, 2021		152,056,808
Beginning balance at Jan. 31, 2021	$ 2,266,320	$ 2	965,670	1,299,656	992
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)	889,791	889,791
Issuance of common stock upon exercise of stock options	$ 37,942		37,942
Issuance of common stock upon vesting of restricted stock units (in shares)		465,285
Shares withheld related to net share settlement (in shares)		(53,625)
Shares withheld related to net share settlement	(16,385)		(16,385)
Stock-based compensation expense	111,476		111,476
Change in other comprehensive income (loss)	(3,681)				(3,681)
Net income	224,425			224,425
Ending balance (in shares) at Jul. 31, 2021		153,358,259
Ending balance at Jul. 31, 2021	2,620,097	$ 2	1,098,703	1,524,081	(2,689)
Beginning balance (in shares) at Apr. 30, 2021		152,800,356
Beginning balance at Apr. 30, 2021	2,444,984	$ 2	1,032,063	1,415,223	(2,304)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)		404,754
Issuance of common stock upon exercise of stock options	20,342		20,342
Issuance of common stock upon vesting of restricted stock units (in shares)		206,774
Shares withheld related to net share settlement (in shares)		(53,625)
Shares withheld related to net share settlement	(16,385)		(16,385)
Stock-based compensation expense	62,683		62,683
Change in other comprehensive income (loss)	(385)				(385)
Net income	108,858			108,858
Ending balance (in shares) at Jul. 31, 2021		153,358,259
Ending balance at Jul. 31, 2021	$ 2,620,097	$ 2	$ 1,098,703	$ 1,524,081	$ (2,689)