Net Income Per Share Attributable to Common Stockholders - Summary of Potential Shares of Common Stock Excluded from Computation of Diluted Net Income Per Share Attributable to Common Stockholders (Details) - shares	3 Months Ended
	Apr. 30, 2020	Apr. 30, 2019
Class A Common Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	247,775	161,650
Class B Common Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	0	19,663
Outstanding stock options | Class A Common Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	205,776	161,650
Outstanding stock options | Class B Common Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	0	19,663
Unvested RSUs | Class A Common Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	41,999	0
Unvested RSUs | Class B Common Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	0	0
Held For Charitable Contributions | Class A Common Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	493,156