Description of Business and Basis of Presentation - Additional Information (Details)			1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 31, 2016 Customer	Jan. 31, 2016 Customer	Jan. 31, 2015 USD ($) $ / shares shares	Jul. 31, 2016 USD ($) Customer	Jul. 31, 2015 USD ($) Customer	Jul. 31, 2016 USD ($) Customer	Jul. 31, 2015 USD ($) Customer	Jan. 31, 2016 USD ($) Customer	Jan. 31, 2015 USD ($) $ / shares shares	Jan. 31, 2014 USD ($)
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Payment of initial public offering costs | $				$ 0	$ 839,000	$ 0	$ 2,172,000
Initial Public Offering
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Issuance of stock of over-allotment option | shares									1,875,000
Public offering price for common stock | $ / shares			$ 14.00						$ 14.00
Net proceeds from initial public offering | $									$ 187,200,000
Underwriting discounts and commissions | $									14,100,000
Initial public offering costs | $			$ 5,700,000
Payment of initial public offering costs | $								$ 2,200,000	$ 2,900,000	$ 588,000
Conversion of stock, shares converted | shares			17,051,820
Deferred issuance cost | $			$ 5,700,000
Class A Common Stock | Initial Public Offering
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Issuance of stock | shares									14,375,000
Redeemable Convertible Preferred Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Issuance of redeemable convertible preferred stock exercise of warrants (in shares) | shares			85,354
Redeemable Convertible Preferred Stock | Initial Public Offering
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Conversion of stock, shares converted | shares			76,238,097
Conversion of redeemable convertible preferred stock to common stock (in shares) | shares			11,904,759
Deemed dividend on the conversion of Series F redeemable convertible preferred stock | $			$ 2,300,000
Series F Redeemable Convertible Preferred Stock | Initial Public Offering
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Conversion of stock, shares converted | shares			7,500,000
Credit Concentration Risk | Accounts Receivable
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of major customer | Customer	0	0		0		0		0
Concentration risk percentage	10.00%	10.00%
Customer Concentration Risk | Revenue
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of major customer | Customer	0			0	0	0	0
Concentration risk percentage				10.00%	10.00%	10.00%	10.00%
Geographic Concentration Risk | Revenue | United States
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Concentration risk percentage				83.00%	80.00%	83.00%	80.00%
Geographic Concentration Risk | Property and Equipment | United States
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Concentration risk percentage	99.50%	99.30%