Stockholders' Equity (Deficit) - Narrative (Details)		6 Months Ended
	Apr. 06, 2017 shares	Jul. 31, 2017 vote $ / shares shares	Jan. 31, 2017 $ / shares shares
Class of Stock [Line Items]
Shares authorized, (in shares)			120,000,000
Common stock par value (in dollars per share) | $ / shares			$ 0.0001
Redeemable Convertible Preferred Stock
Class of Stock [Line Items]
Redeemable convertible preferred stock converted to common class B stock (in shares)	59,491,640
Redeemable preferred stock outstanding (in shares)		0
Class A Common Stock
Class of Stock [Line Items]
Shares authorized, (in shares)		1,000,000,000
Common stock par value (in dollars per share) | $ / shares		$ 0.0001
Common stock outstanding (in shares)		16,934,899
Number of votes per share | vote		1
Class B Common Stock
Class of Stock [Line Items]
Common class B stock after conversion of redeemable convertible stock (in shares)	59,491,640
Shares authorized, (in shares)		120,000,000
Common stock par value (in dollars per share) | $ / shares		$ 0.0001
Common stock outstanding (in shares)		78,552,887
Number of votes per share | vote		10