Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Oct. 28, 2017	Dec. 15, 2017
Document Information [Line Items]
Document type	10-Q
Amendment flag	false
Document period end date	Oct. 28, 2017
Document fiscal year focus	2018
Document fiscal period focus	Q1
Trading Symbol	SFIX
Entity registrant name	Stitch Fix, Inc.
Entity central index key	0001576942
Current fiscal year end date	--07-28
Entity filer category	Non-accelerated Filer
Class A Common Stock
Document Information [Line Items]
Entity common stock, shares outstanding		9,175,557
Class B Common Stock
Document Information [Line Items]
Entity common stock, shares outstanding		87,748,954

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Oct. 28, 2017	Jul. 29, 2017
Current assets:
Cash	$ 131,096	$ 110,608
Restricted cash	250	250
Inventory, net	87,576	67,592
Prepaid expenses and other current assets	16,584	19,312
Total current assets	235,506	197,762
Property and equipment, net	29,545	26,733
Deferred tax assets	21,357	19,991
Restricted cash, net of current portion	9,100	9,100
Other long-term assets	3,203	3,619
Total assets	298,711	257,205
Current liabilities:
Accounts payable	58,519	44,238
Accrued liabilities	64,315	46,363
Preferred stock warrant liability	17,608	26,679
Gift card liability	5,071	5,190
Deferred revenue	8,813	7,150
Other current liabilities	4,645	4,298
Total current liabilities	158,971	133,918
Deferred rent, net of current portion	11,354	11,781
Other long-term liabilities	7,897	7,423
Total liabilities	178,222	153,122
Commitments and contingencies (Note 6)
Convertible preferred stock, $0.00002 par value – 60,577,280 shares authorized as of October 28, 2017 and July 29, 2017; 59,511,055 shares issued and outstanding as of October 28, 2017 and July 29, 2017; aggregate liquidation preference of $42,389 as of October 28, 2017 and July 29, 2017	42,222	42,222
Stockholders’ equity:
Common stock, $0.00002 par value – 100,000,000 shares authorized as of October 28, 2017 and July 29, 2017; 27,026,292 and 26,834,535 shares issued and outstanding as of October 28, 2017 and July 29, 2017, respectively	1	1
Additional paid-in capital	29,920	27,002
Retained earnings	48,346	34,858
Total stockholders’ equity	78,267	61,861
Total liabilities, convertible preferred stock and stockholders’ equity	$ 298,711	$ 257,205

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Oct. 28, 2017	Jul. 29, 2017
Statement Of Financial Position [Abstract]
Convertible preferred stock, par value	$ 0.00002	$ 0.00002
Convertible preferred stock, shares authorized	60,577,280	60,577,280
Convertible preferred stock, shares issued	59,511,055	59,511,055
Convertible preferred stock, shares outstanding	59,511,055	59,511,055
Convertible preferred stock, aggregate liquidation preference	$ 42,389	$ 42,389
Common stock, par value	$ 0.00002	$ 0.00002
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	27,026,292	26,834,535
Common stock, shares outstanding	27,026,292	26,834,535

Condensed Consolidated Statements of Operations and Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Oct. 28, 2017	Oct. 29, 2016
Income Statement [Abstract]
Revenue, net	$ 295,563	$ 236,004
Cost of goods sold	166,548	125,926
Gross profit	129,015	110,078
Selling, general and administrative expenses	119,471	83,550
Operating income	9,544	26,528
Remeasurement of preferred stock warrant liability	(9,071)	1,503
Other income, net	(17)	(7)
Income before income taxes	18,632	25,032
Provision for income taxes	5,144	11,789
Net income and comprehensive income	13,488	13,243
Net income attributable to common stockholders:
Basic	3,915	3,595
Diluted	$ 1,347	$ 4,055
Earnings per share attributable to common stockholders:
Basic	$ 0.15	$ 0.15
Diluted	$ 0.04	$ 0.14
Shares used to compute earnings per share attributable to common stockholders:
Basic	26,329,495	24,349,434
Diluted	33,262,082	28,940,058

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity - 3 months ended Oct. 28, 2017 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Convertible Preferred Stock
Beginning balance, shares at Jul. 29, 2017	59,511,055				59,511,055
Beginning balance at Jul. 29, 2017	$ 42,222				$ 42,222
Ending balance, shares at Oct. 28, 2017	59,511,055				59,511,055
Ending balance at Oct. 28, 2017	$ 42,222				$ 42,222
Beginning balance at Jul. 29, 2017	61,861	$ 1	$ 27,002	$ 34,858
Beginning balance, shares at Jul. 29, 2017		26,834,535
Issuance of common stock upon exercise of stock options	444		444
Issuance of common stock upon exercise of stock options, shares		211,236
Repurchase of common stock related to early exercised options, shares		(19,479)
Vesting of early exercised options	315		315
Stock-based compensation	2,159		2,159
Net income	13,488			13,488
Ending balance at Oct. 28, 2017	$ 78,267	$ 1	$ 29,920	$ 48,346
Ending balance, shares at Oct. 28, 2017		27,026,292

Condensed Consolidated Statements of Cash Flow - USD ($) $ in Thousands	3 Months Ended
	Oct. 28, 2017	Oct. 29, 2016
Cash Flows from Operating Activities
Net income	$ 13,488	$ 13,243
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income taxes	(1,366)	(648)
Remeasurement of preferred stock warrant liability	(9,071)	1,503
Inventory reserve	4,224	1,933
Stock-based compensation expense	2,038	610
Depreciation and amortization	2,270	1,461
Loss on disposal of property and equipment	131	27
Change in operating assets and liabilities:
Inventory	(24,208)	(10,142)
Prepaid expenses and other assets	4,084	(34)
Accounts payable	13,967	7,682
Accrued liabilities	16,942	21,119
Deferred revenue	1,663	2,173
Gift card liability	(119)	(48)
Other liabilities	748	2,725
Net cash provided by operating activities	24,791	41,604
Cash Flows from Investing Activities
Purchase of property and equipment	(4,180)	(5,478)
Proceeds from sale of property and equipment		31
Net cash used in investing activities	(4,180)	(5,447)
Cash Flows from Financing Activities
Proceeds from the exercise of stock options	444	206
Repurchase of common stock related to early exercised options	(39)
Payment of deferred offering costs	(528)
Net cash (used in) provided by financing activities	(123)	206
Net increase in cash and restricted cash	20,488	36,363
Cash and restricted cash at beginning of period	119,958	101,492
Cash and restricted cash at end of period	140,446	137,855
Components of cash and restricted cash
Cash	131,096	127,114
Restricted cash	250	1,391
Restricted cash, net of current portion	9,100	9,350
Cash and restricted cash at end of period	140,446	137,855
Supplemental Disclosure
Cash paid for income taxes		8,749
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Purchases of property and equipment included in accounts payable and accrued liabilities	1,022	4,303
Capitalized stock-based compensation	121	22
Vesting of early exercised options	315	$ 229
Deferred offering costs included in accounts payable and accrued liabilities	$ 920

Description of Business

3 Months Ended

Oct. 28, 2017

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Description of Business

1.	Description of Business

Stitch Fix, Inc. (“we,” “our,” “us” or “the Company”) delivers one-to-one personalization to our clients through the combination of data science and human judgment. Our stylists hand select items from a broad selection of merchandise. Stylists pair their own judgment with our analysis of client and merchandise data to provide a personalized shipment of apparel, shoes and accessories suited to each client’s needs. We call each of these unique shipments a Fix. After receiving a Fix, our clients purchase the items they want to keep and return the other items. We were incorporated in Delaware and have operations in the United States.

Initial Public Offering

On November 16, 2017, we completed an initial public offering (“IPO”), in which we issued and sold 8,000,000 shares of our Class A common stock at a public offering price of $15.00 per share. We received approximately $110.4 million in net proceeds after deducting $6.2 million of underwriting discounts and $3.4 million in offering costs. Upon the closing of the IPO, all of the outstanding shares of common stock were reclassified into Class B common stock, all of the outstanding shares of convertible preferred stock automatically converted into 59,511,055 shares of Class B common stock and all of the outstanding preferred stock warrants were automatically exercised for 1,066,225 shares of Class B common stock. Subsequent to the closing of the IPO, there were no shares of preferred stock or preferred stock warrants outstanding. In December 2017, we issued an additional 1,175,557 shares of Class A common stock at a price of $15.00 per share following the underwriters’ exercise of their option to purchase additional shares and received $16.7 million in net proceeds after deducting underwriting discounts and expenses. The condensed consolidated financial statements as of October 28, 2017, including share and per share amounts, do not give effect to the sale of shares of Class A common stock in connection with the IPO, conversion of the convertible preferred stock, or the exercise of the preferred stock warrants, as the IPO was completed subsequent to October 28, 2017.

Summary of Significant Accounting Policies

3 Months Ended

Oct. 28, 2017

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2.	Summary of Significant Accounting Policies

Basis of Presentation

Our fiscal year is a 52-week or 53-week period ending on the Saturday closest to July 31. The fiscal years ended July 29, 2017 (“2017”) and July 28, 2018 (“2018”) each consist of 52 weeks.

The unaudited condensed consolidated financial statements include the accounts of Stitch Fix, Inc. and our wholly owned subsidiaries, and have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) and following the requirements of the Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by GAAP can be condensed or omitted. These financial statements have been prepared on the same basis as our annual financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for the fair statement of our financial information. These interim results are not necessarily indicative of the results to be expected for the fiscal year ending July 28, 2018 or for any other interim period or for any other future year. All intercompany balances and transactions have been eliminated in consolidation.

The accompanying unaudited condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto for the fiscal year ended July 29, 2017 contained in our prospectus filed pursuant to Rule 424(b) under the Securities Act of 1933, as amended, with the SEC on November 17, 2017.

Use of Estimates

The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts in our condensed consolidated financial statements and accompanying footnotes. Significant estimates and assumptions are used for inventory, stock-based compensation expense, common stock valuation, remeasurement of preferred stock warrant liability, revenue recognition and income taxes. Actual results could differ from those estimates and such differences may be material to the condensed consolidated financial statements.

Restricted Cash

Restricted cash represents cash balances held in segregated accounts collateralizing letters of credit for our leased properties as of October 28, 2017 and July 29, 2017.

Deferred Offering Costs

Deferred offering costs, which consist of direct incremental legal, consulting, banking and accounting fees relating to the IPO are capitalized and will be offset against proceeds upon the consummation of the IPO, which became effective on November 16, 2017 (See Note 1). As of October 28, 2017 and July 29, 2017, there were $3,327,000 and $2,387,000 capitalized deferred offering costs in prepaid expenses and other current assets on the condensed consolidated balance sheet, respectively.

Concentration of Credit Risks

The majority of our cash is held by three financial institutions within the United States. Our cash balances held by these institutions may exceed federally insured limits. The associated risk of concentration for cash is mitigated by banking with credit-worthy institutions. No client accounted for greater than 10% of total revenue, net for the three months ended October 28, 2017 and October 29, 2016.

Recently Issued Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers (Topic 606), or ASU 2014-09, which amended the existing FASB Accounting Standards Codification. ASU 2014-09 establishes a principle for recognizing revenue upon the transfer of promised goods or services to customers, in an amount that reflects the expected consideration received in exchange for those goods or services and also provides guidance on the recognition of costs related to obtaining and fulfilling customer contracts. We expect to adopt this standard in our first quarter of fiscal 2019. We are in the process of evaluating the impact this standard will have on our consolidated financial statements. As part of our process, we are still assessing the adoption methodology, which allows the amendment to be applied either retrospectively to each prior period presented or with the cumulative effect recognized as of the date of initial application.

In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), or ASU 2016-02, which requires lessees to record most leases on their balance sheets but recognize the expenses on their income statements in a manner similar to current practice. ASU 2016-02 states that a lessee would recognize a lease liability for the obligation to make lease payments and a right-to-use asset for the right to use the underlying asset for the lease term. We expect to adopt this standard in our first quarter of fiscal 2020. We are currently evaluating the impact that this standard will have on our consolidated financial statements but we expect that it will result in a substantial increase in our long-term assets and liabilities.

In March 2016, the FASB issued ASU No. 2016-09, Compensation – Stock Compensation: Improvements to Employee Share-Based Payment Accounting (Topic 718), which simplifies the accounting and reporting of share-based payment transactions, including adjustments to how excess tax benefits and payments for tax withholdings should be classified and provides the election to eliminate the estimate for forfeitures. Upon adoption, ASU 2016-09 requires that excess tax benefits for share-based payments be recorded as a reduction of income tax expense and reflected within operating cash flows, rather than being recorded within equity and reflected within financing cash flows. ASU 2016-09 also permits the repurchase of more of an employee’s shares for tax withholding purposes without triggering liability accounting, clarifies that all cash payments made on an employee’s behalf for withheld shares should be presented as a financing activity on the Company’s statement of cash flows, and provides an accounting policy election to account for forfeitures as they occur. We adopted this standard in our first quarter of 2018. We made an accounting policy election to continue to estimate forfeitures. All excess tax benefits and tax deficiencies related to share-based payment awards are now reflected in the consolidated statement of operations and comprehensive income as a component of the provision for income taxes on a prospective basis, whereas they were recognized in equity under the previous guidance. Additionally, excess tax benefits related to share-based payment awards are now reflected in operating activities, along with other income tax related cash flows, in our consolidated statement of cash flows on a prospective basis. The adoption did not have a material impact on our consolidated financial statements.

In October 2016, the FASB issued ASU No. 2016-16, Income Taxes: Intra-Entity Transfers of Assets Other Than Inventory (Topic 740), which amends existing guidance on the recognition of current and deferred income tax impacts for intra-entity asset transfers other than inventory. This amendment should be applied on a modified retrospective basis. We expect to adopt this standard in fiscal 2019 and are currently evaluating the impact that it will have on our consolidated financial statements.

Fair Value Measurements

3 Months Ended

Oct. 28, 2017

Fair Value Disclosures [Abstract]

Fair Value Measurements

3.	Fair Value Measurements

We disclose and recognize the fair value of our assets and liabilities using a hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the measurement date. The guidance establishes three levels of the fair value hierarchy as follows:

Level 1: Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date;

Level 2: Inputs are observable, unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and

Level 3: Unobservable inputs that are significant to the measurement of the fair value of the assets or liabilities that are supported by little or no market data.

Our financial instruments consist of cash, accounts payable, accrued liabilities and the preferred stock warrant liability. At October 28, 2017 and July 29, 2017, the carrying values of cash, accounts payable and accrued liabilities approximated fair value due to their short-term maturities.

The following table sets forth our financial instruments that were measured at fair value on a recurring basis based on the fair value hierarchy (in thousands):

	October 28, 2017
	Level 1		Level 2		Level 3		Total
Financial Liabilities:
Preferred stock warrant liability	$	—	$	—	$	17,608	$	17,608
Total	$	—	$	—	$	17,608	$	17,608

	July 29, 2017
	Level 1		Level 2		Level 3		Total
Financial Liabilities:
Preferred stock warrant liability	$	—	$	—	$	26,679	$	26,679
Total	$	—	$	—	$	26,679	$	26,679

There were no transfers of financial assets or liabilities into or out of Level 1, Level 2 or Level 3 for the three months ended October 28, 2017 and October 29, 2016. The key assumptions used in the Black-Scholes option-pricing model for the valuation of the preferred stock warrant liability upon remeasurement were as follows:

	Three Months Ended
	October 28, 2017			October 29, 2016
Expected term (in years)		2.0			5.3
Fair value of underlying shares	$	16.53		$	8.89
Volatility		39.2	%		40.2	%
Risk free interest rate		1.6	%		1.4	%
Dividend yield		—	%		—	%

Generally, increases or decreases in the fair value of the underlying convertible preferred stock would result in a directionally similar impact in the fair value measurement of the associated warrant liability.

The following table sets forth a summary of the changes in the fair value of the preferred stock warrant liability (in thousands):

	Three Months Ended
	October 28, 2017
Balance at July 29, 2017	$	26,679
Change in fair value		(9,071	)
Ending Balance at October 28, 2017	$	17,608

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Accrued Liabilities

3 Months Ended

Oct. 28, 2017

Accrued Liabilities Current [Abstract]

Accrued Liabilities

4.	Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):

	October 28, 2017		July 29, 2017
Inventory purchases	$	30,193	$	11,186
Advertising		11,242		9,995
Compensation and related benefits		4,848		9,632
Sales taxes		4,506		3,702
Shipping and freight		4,083		3,390
Other		9,443		8,458
Total accrued liabilities	$	64,315	$	46,363

Preferred Stock Warrant Liability

3 Months Ended

Oct. 28, 2017

Equity [Abstract]

Preferred Stock Warrant Liability

5.	Preferred Stock Warrant Liability

In 2012 and 2013, in connection with financing arrangements, we issued warrants to purchase shares of our convertible preferred stock. For one of the financing arrangements, we issued warrants to purchase 375,230 shares of Series Seed convertible preferred stock at an exercise price of $0.1066 per share and 66,265 shares of Series A convertible preferred stock at an exercise price of $0.22636 per share. For the second financing arrangement, we issued warrants for the purchase of, at the warrant holder’s option, either (a) 624,730 shares of Series A-1 convertible preferred stock at an exercise price of $0.2401 per share or (b) 308,315 shares of Series B convertible preferred stock at an exercise price of $0.486516 per share. Prior to their automatic exercise in connection with the IPO, as described below, the warrants were exercisable for and expired ten years from the date of issuance. The warrants remained outstanding as of October 28, 2017 and July 29, 2017.

In November 2017, these warrants were automatically exercised in connection with the completion of the IPO and the preferred stock warrant liability was reclassed to stockholder’s equity.

Commitments and Contingencies

3 Months Ended

Oct. 28, 2017

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

6.	Commitments and Contingencies

Contingencies

We record a loss contingency when it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. We also disclose material contingencies when we believe a loss is not probable but reasonably possible. Accounting for contingencies requires us to use judgment related to both the likelihood of a loss and the estimate of the amount or range of loss. Although we cannot predict with assurance the outcome of any litigation or tax matters, we do not believe there are currently any such actions that, if resolved unfavorably, would have a material impact on our operating results, financial position and cash flows.

Indemnifications

In the ordinary course of business, we may provide indemnifications of varying scope and terms to vendors, directors, officers and other parties with respect to certain matters. We have not incurred any material costs as a result of such indemnifications and have not accrued any liabilities related to such obligations in our condensed consolidated financial statements.

Stock Based Compensation

3 Months Ended

Oct. 28, 2017

Stock Based Compensation

7.	Stock-Based Compensation

2011 Equity Incentive Plan

In 2011, we adopted the 2011 Equity Incentive Plan (the “2011 Plan”). The 2011 Plan provided for the granting of stock-based awards to employees, including directors and non-employees under terms and provisions established by the board of directors. The number of shares authorized for issuance under the 2011 Plan was 23,223,374 as of October 28, 2017, of which 1,726,679 were available for grant.

The 2011 Plan allowed for the grant incentive stock options or nonqualified stock options as well as restricted stock units, restricted stock and stock appreciation rights. As of October 28, 2017, we had only granted incentive and nonqualified stock options under the 2011 Plan. Employee stock options generally vest 25% on the first anniversary of the grant date with the remaining vesting ratably over the next three years. Options generally expire after 10 years. Stock option activity under the 2011 Plan is as follows:

				Options Outstanding
	Shares Available for Grant			Number of Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (in Years)		Aggregate Intrinsic Value
											(In thousands)
Balance – July 29, 2017		2,023,424			10,218,912		$	7.12		8.53	$	166,670
Repurchased		19,479
Granted		(867,865	)		867,865		$	23.43
Exercised		—			(211,236	)	$	2.10
Cancelled		551,641			(551,641	)	$	4.01
Balance – October 28, 2017		1,726,679			10,323,900		$	8.76		8.45	$	87,531

The aggregate intrinsic value is the difference between the current fair value of the underlying common stock and the exercise price for in-the-money stock options.

Stock-Based Compensation Expense

Stock-based compensation expense for options granted to employees was $2,038,000 and $552,000 for the three months ended October 28, 2017 and October 29, 2016, respectively. Stock-based compensation expense for options granted to non-employees was none for the three months ended October 28, 2017 and $58,000 for the three months ended October 29, 2016. Stock-based compensation expense is included in selling, general and administrative expenses in our condensed consolidated statements of operations.

The weighted-average grant date fair value of options granted during the three months ended October 28, 2017 and October 29, 2016 was $7.55 per share and $2.53 per share, respectively. As of October 28, 2017, the total unrecognized compensation expense related to unvested options, net of estimated forfeitures, was $36.8 million which we expect to recognize over an estimated weighted average period of 3.6 years.

We record stock-based compensation of stock options granted to employees by estimating the fair value of stock-based awards using the Black-Scholes option pricing model and amortizing the fair value of the stock-based awards granted over the applicable vesting period of the awards on a straight-line basis. The fair value of stock options granted to employees was estimated at the grant date using the Black- Scholes option-pricing model with the following assumptions:

	Three Months Ended
	October 28, 2017	October 29, 2016
Expected term (in years)	5.6 – 6.5	5.4 – 6.5
Volatility	42.1 – 43.5%	44.4 – 46.0%
Risk free interest rate	1.9 – 2.0%	1.3 – 1.5%
Dividend yield	— %	— %

In July 2017, we granted options to certain members of our executive management team to purchase an aggregate of 1,097,463 shares of common stock which had both a service-based condition and a liquidity event-related performance condition. Such options vest ratably over the 24 month period following the fourth anniversary of the grant date, subject to an IPO occurring within 12 months of the grant date and the option holder’s continuous service through each vesting date. The aggregate grant-date fair value of such option awards was $14.0 million. As of October 28, 2017, achievement of the performance condition was not deemed probable and accordingly, no expense was recognized related to these option awards through October 28, 2017.

The achievement of the performance condition was deemed probable upon consummation of the IPO in November 2017 at which time we recorded a cumulative catch-up stock based compensation expense related to periods prior to the IPO.

Income Taxes

3 Months Ended

Oct. 28, 2017

Income Tax Disclosure [Abstract]

Income Taxes

8.	Income Taxes

The following table summarizes our effective tax rate from income for the periods presented:

	Three Months Ended
	October 28, 2017			October 29, 2016
Income before income taxes	$	18,632		$	25,032
Provisions for income taxes		5,144			11,789
Effective tax rate		27.6	%		47.1	%

We are subject to income taxes in the United States. Our effective tax rate for the three months ended October 28, 2017, differs from the federal statutory income tax rate primarily due to certain nondeductible expenses, effect of state taxes, partially offset by the benefit from the nonincludible gain on remeasurement of the preferred stock warrant liability.

Our effective tax rate for the three months ended October 29, 2016 differs from the federal statutory income tax rate primarily due to certain nondeductible expenses, effect of state taxes, and the nondeductible loss on remeasurement of the preferred stock warrant liability.

Earnings (Loss) Per Share Attributable to Common Stockholders

3 Months Ended

Oct. 28, 2017

Earnings Per Share [Abstract]

Earnings (Loss) Per Share Attributable to Common Stockholders

9.	Earnings (Loss) Per Share Attributable to Common Stockholders

A reconciliation of the numerator and denominator used in the calculation of the basic and diluted earnings per share attributable to common stockholders is as follows (in thousands except share and per share amounts):

	Three Months Ended
	October 28, 2017			October 29, 2016
Numerator:
Net income	$	13,488		$	13,243
Less: noncumulative dividends to preferred stockholders		(635	)		(635	)
Less: undistributed earnings to participating securities		(8,938	)		(9,013	)
Net income attributable to common stockholders - basic		3,915			3,595
Less: change in fair value of preferred stock warrant liability (net of tax)		(9,071	)		—
Add: adjustments to undistributed earnings to participating securities		6,503			460
Net income attributable to common stockholders - diluted		1,347			4,055

Denominator:
Weighted-average shares of common stock - basic		26,329,495			24,349,434
Effect of dilutive stock options		5,876,621			4,590,624
Effect of potentially dilutive preferred stock warrants		1,055,966			—
Weighted-average shares of common stock - diluted		33,262,082			28,940,058
Earnings per share attributable to common stockholders:
Basic	$	0.15		$	0.15
Diluted	$	0.04		$	0.14

The following common stock equivalents were excluded from the computation of diluted earnings (loss) per share for the periods presented because including them would have been antidilutive:

	Three Months Ended
	October 28, 2017		October 29, 2016
Convertible preferred stock		59,511,055		59,511,055
Preferred stock warrants		—		1,066,225
Stock options to purchase common stock		954,706		712,925
Total		60,465,761		61,290,205

Subsequent Events

3 Months Ended

Oct. 28, 2017

Subsequent Events [Abstract]

Subsequent Events

10.	Subsequent Events

Initial Public Offering

On November 16, 2017, we completed an IPO in which we issued and sold 8,000,000 shares of our Class A common stock at a public offering price of $15.00 per share. We received approximately $110.4 million in net proceeds after deducting $6.2 million of underwriting discounts and $3.4 million in offering costs. Upon the closing of the IPO, all of our outstanding shares of common stock were reclassified into Class B common stock, all of our outstanding shares of convertible preferred stock automatically converted into 59,511,055 shares of Class B common stock and our outstanding preferred stock warrants were automatically exercised into 1,066,225 shares of Class B common stock. Subsequent to the closing of the IPO, there were no shares of preferred stock or preferred stock warrants outstanding.

In December 2017, we issued an additional 1,175,557 shares of Class A common stock at a price of $15.00 per share following the underwriters’ exercise of their option to purchase additional shares and received proceeds of $16.7 million, net of underwriting discounts and commissions.

2017 Incentive Plan

Our board of directors and stockholders adopted our 2017 Incentive Plan (the “2017 Plan”) in November 2017. The 2017 Plan became effective upon, and no stock award was permitted to be granted prior to, the execution and delivery of the underwriting agreement related to the IPO. Our 2017 Plan provides for the grant of incentive stock options to employees, including employees of any parent or subsidiary, and for the grant of nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance stock awards, performance cash awards and other forms of stock awards to employees, directors and consultants, including employees and consultants of our affiliates.

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Oct. 28, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation Our fiscal year is a 52-week or 53-week period ending on the Saturday closest to July 31. The fiscal years ended July 29, 2017 (“2017”) and July 28, 2018 (“2018”) each consist of 52 weeks. The unaudited condensed consolidated financial statements include the accounts of Stitch Fix, Inc. and our wholly owned subsidiaries, and have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) and following the requirements of the Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by GAAP can be condensed or omitted. These financial statements have been prepared on the same basis as our annual financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for the fair statement of our financial information. These interim results are not necessarily indicative of the results to be expected for the fiscal year ending July 28, 2018 or for any other interim period or for any other future year. All intercompany balances and transactions have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto for the fiscal year ended July 29, 2017 contained in our prospectus filed pursuant to Rule 424(b) under the Securities Act of 1933, as amended, with the SEC on November 17, 2017.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts in our condensed consolidated financial statements and accompanying footnotes. Significant estimates and assumptions are used for inventory, stock-based compensation expense, common stock valuation, remeasurement of preferred stock warrant liability, revenue recognition and income taxes. Actual results could differ from those estimates and such differences may be material to the condensed consolidated financial statements.
Restricted Cash	Restricted Cash Restricted cash represents cash balances held in segregated accounts collateralizing letters of credit for our leased properties as of October 28, 2017 and July 29, 2017.
Deferred Offering Costs	Deferred Offering Costs Deferred offering costs, which consist of direct incremental legal, consulting, banking and accounting fees relating to the IPO are capitalized and will be offset against proceeds upon the consummation of the IPO, which became effective on November 16, 2017 (See Note 1). As of October 28, 2017 and July 29, 2017, there were $3,327,000 and $2,387,000 capitalized deferred offering costs in prepaid expenses and other current assets on the condensed consolidated balance sheet, respectively.
Concentration of Credit Risks	Concentration of Credit Risks The majority of our cash is held by three financial institutions within the United States. Our cash balances held by these institutions may exceed federally insured limits. The associated risk of concentration for cash is mitigated by banking with credit-worthy institutions. No client accounted for greater than 10% of total revenue, net for the three months ended October 28, 2017 and October 29, 2016.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers (Topic 606), or ASU 2014-09, which amended the existing FASB Accounting Standards Codification. ASU 2014-09 establishes a principle for recognizing revenue upon the transfer of promised goods or services to customers, in an amount that reflects the expected consideration received in exchange for those goods or services and also provides guidance on the recognition of costs related to obtaining and fulfilling customer contracts. We expect to adopt this standard in our first quarter of fiscal 2019. We are in the process of evaluating the impact this standard will have on our consolidated financial statements. As part of our process, we are still assessing the adoption methodology, which allows the amendment to be applied either retrospectively to each prior period presented or with the cumulative effect recognized as of the date of initial application. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), or ASU 2016-02, which requires lessees to record most leases on their balance sheets but recognize the expenses on their income statements in a manner similar to current practice. ASU 2016-02 states that a lessee would recognize a lease liability for the obligation to make lease payments and a right-to-use asset for the right to use the underlying asset for the lease term. We expect to adopt this standard in our first quarter of fiscal 2020. We are currently evaluating the impact that this standard will have on our consolidated financial statements but we expect that it will result in a substantial increase in our long-term assets and liabilities. In March 2016, the FASB issued ASU No. 2016-09, Compensation – Stock Compensation: Improvements to Employee Share-Based Payment Accounting (Topic 718), which simplifies the accounting and reporting of share-based payment transactions, including adjustments to how excess tax benefits and payments for tax withholdings should be classified and provides the election to eliminate the estimate for forfeitures. Upon adoption, ASU 2016-09 requires that excess tax benefits for share-based payments be recorded as a reduction of income tax expense and reflected within operating cash flows, rather than being recorded within equity and reflected within financing cash flows. ASU 2016-09 also permits the repurchase of more of an employee’s shares for tax withholding purposes without triggering liability accounting, clarifies that all cash payments made on an employee’s behalf for withheld shares should be presented as a financing activity on the Company’s statement of cash flows, and provides an accounting policy election to account for forfeitures as they occur. We adopted this standard in our first quarter of 2018. We made an accounting policy election to continue to estimate forfeitures. All excess tax benefits and tax deficiencies related to share-based payment awards are now reflected in the consolidated statement of operations and comprehensive income as a component of the provision for income taxes on a prospective basis, whereas they were recognized in equity under the previous guidance. Additionally, excess tax benefits related to share-based payment awards are now reflected in operating activities, along with other income tax related cash flows, in our consolidated statement of cash flows on a prospective basis. The adoption did not have a material impact on our consolidated financial statements. In October 2016, the FASB issued ASU No. 2016-16, Income Taxes: Intra-Entity Transfers of Assets Other Than Inventory (Topic 740), which amends existing guidance on the recognition of current and deferred income tax impacts for intra-entity asset transfers other than inventory. This amendment should be applied on a modified retrospective basis. We expect to adopt this standard in fiscal 2019 and are currently evaluating the impact that it will have on our consolidated financial statements.

Fair Value Measurements (Tables)

3 Months Ended

Oct. 28, 2017

Text Block [Abstract]

Schedule of Financial Instruments Measured at Fair Value on Recurring Basis Based on Fair Value Hierarchy

The following table sets forth our financial instruments that were measured at fair value on a recurring basis based on the fair value hierarchy (in thousands):

	October 28, 2017
	Level 1		Level 2		Level 3		Total
Financial Liabilities:
Preferred stock warrant liability	$	—	$	—	$	17,608	$	17,608
Total	$	—	$	—	$	17,608	$	17,608

	July 29, 2017
	Level 1		Level 2		Level 3		Total
Financial Liabilities:
Preferred stock warrant liability	$	—	$	—	$	26,679	$	26,679
Total	$	—	$	—	$	26,679	$	26,679

Schedule of Key Assumptions Used for Valuation of Preferred Stock Warrant Liability

The key assumptions used in the Black-Scholes option-pricing model for the valuation of the preferred stock warrant liability upon remeasurement were as follows:

	Three Months Ended
	October 28, 2017			October 29, 2016
Expected term (in years)		2.0			5.3
Fair value of underlying shares	$	16.53		$	8.89
Volatility		39.2	%		40.2	%
Risk free interest rate		1.6	%		1.4	%
Dividend yield		—	%		—	%

Schedule of Changes in Fair Value of Preferred Stock Warrant Liability

The following table sets forth a summary of the changes in the fair value of the preferred stock warrant liability (in thousands):

	Three Months Ended
	October 28, 2017
Balance at July 29, 2017	$	26,679
Change in fair value		(9,071	)
Ending Balance at October 28, 2017	$	17,608

Accrued Liabilities (Tables)

3 Months Ended

Oct. 28, 2017

Accrued Liabilities Current [Abstract]

Schedule of Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):

	October 28, 2017		July 29, 2017
Inventory purchases	$	30,193	$	11,186
Advertising		11,242		9,995
Compensation and related benefits		4,848		9,632
Sales taxes		4,506		3,702
Shipping and freight		4,083		3,390
Other		9,443		8,458
Total accrued liabilities	$	64,315	$	46,363

Stock Based Compensation (Tables)

3 Months Ended

Oct. 28, 2017

Summary of Stock Option Activity Under 2011 Stock Plan

Stock option activity under the 2011 Plan is as follows:

				Options Outstanding
	Shares Available for Grant			Number of Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (in Years)		Aggregate Intrinsic Value
											(In thousands)
Balance – July 29, 2017		2,023,424			10,218,912		$	7.12		8.53	$	166,670
Repurchased		19,479
Granted		(867,865	)		867,865		$	23.43
Exercised		—			(211,236	)	$	2.10
Cancelled		551,641			(551,641	)	$	4.01
Balance – October 28, 2017		1,726,679			10,323,900		$	8.76		8.45	$	87,531

Summary of Assumptions Used in Black-Scholes Option-Pricing Model to Determine Fair Value of Stock Options

The fair value of stock options granted to employees was estimated at the grant date using the Black- Scholes option-pricing model with the following assumptions:

	Three Months Ended
	October 28, 2017	October 29, 2016
Expected term (in years)	5.6 – 6.5	5.4 – 6.5
Volatility	42.1 – 43.5%	44.4 – 46.0%
Risk free interest rate	1.9 – 2.0%	1.3 – 1.5%
Dividend yield	— %	— %

Income Taxes (Tables)

3 Months Ended

Oct. 28, 2017

Income Tax Disclosure [Abstract]

Schedule of Effective Tax Rate from Income

The following table summarizes our effective tax rate from income for the periods presented:

	Three Months Ended
	October 28, 2017			October 29, 2016
Income before income taxes	$	18,632		$	25,032
Provisions for income taxes		5,144			11,789
Effective tax rate		27.6	%		47.1	%

Earnings (Loss) Per Share Attributable to Common Stockholders (Tables)

3 Months Ended

Oct. 28, 2017

Earnings Per Share [Abstract]

Reconciliation of Numerator and Denominator Used in Calculation of Basic and Diluted Earnings Per Share

	Three Months Ended
	October 28, 2017			October 29, 2016
Numerator:
Net income	$	13,488		$	13,243
Less: noncumulative dividends to preferred stockholders		(635	)		(635	)
Less: undistributed earnings to participating securities		(8,938	)		(9,013	)
Net income attributable to common stockholders - basic		3,915			3,595
Less: change in fair value of preferred stock warrant liability (net of tax)		(9,071	)		—
Add: adjustments to undistributed earnings to participating securities		6,503			460
Net income attributable to common stockholders - diluted		1,347			4,055

Denominator:
Weighted-average shares of common stock - basic		26,329,495			24,349,434
Effect of dilutive stock options		5,876,621			4,590,624
Effect of potentially dilutive preferred stock warrants		1,055,966			—
Weighted-average shares of common stock - diluted		33,262,082			28,940,058
Earnings per share attributable to common stockholders:
Basic	$	0.15		$	0.15
Diluted	$	0.04		$	0.14

Schedule of Common Stock Equivalents Excluded from Computation of Diluted Earnings (Loss) Per Share

The following common stock equivalents were excluded from the computation of diluted earnings (loss) per share for the periods presented because including them would have been antidilutive:

	Three Months Ended
	October 28, 2017		October 29, 2016
Convertible preferred stock		59,511,055		59,511,055
Preferred stock warrants		—		1,066,225
Stock options to purchase common stock		954,706		712,925
Total		60,465,761		61,290,205

Description of Business - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended
	Dec. 20, 2017	Nov. 16, 2017	Oct. 28, 2017	Nov. 17, 2017
Class Of Stock [Line Items]
Offering costs			$ 528
Subsequent Event
Class Of Stock [Line Items]
Shares of preferred stock outstanding				0
Subsequent Event \| Preferred Stock Warrants
Class Of Stock [Line Items]
Preferred stock warrants outstanding				0
Subsequent Event \| IPO
Class Of Stock [Line Items]
Net proceeds from IPO		$ 110,400
Underwriting discounts		6,200
Offering costs		$ 3,400
Subsequent Event \| IPO \| Class A Common Stock
Class Of Stock [Line Items]
Stock issued during period		8,000,000
Shares Issued, price per share		$ 15.00
Subsequent Event \| IPO \| Class B Common Stock
Class Of Stock [Line Items]
Convertible preferred stock converted		59,511,055
Outstanding preferred stock warrants exercised		1,066,225
Subsequent Event \| Underwriters' Over-Allotment Option \| Class A Common Stock
Class Of Stock [Line Items]
Stock issued during period	1,175,557
Shares Issued, price per share	$ 15.00
Net proceeds after deducting underwriting discounts and expenses	$ 16,700

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	Oct. 28, 2017	Jul. 29, 2017
IPO
Accounting Policies [Line Items]
Deferred Offering Costs	$ 3,327,000	$ 2,387,000

Fair Value Measurements - Schedule of Financial Instruments Measured at Fair Value on Recurring Basis Based on Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Oct. 28, 2017	Jul. 29, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Liabilities	$ 17,608	$ 26,679
Preferred Stock Warrant Liability
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Liabilities	17,608	26,679
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Liabilities	17,608	26,679
Level 3 \| Preferred Stock Warrant Liability
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Liabilities	$ 17,608	$ 26,679

Fair Value Measurements - Additional Information (Details)	Oct. 28, 2017 USD ($)
Fair Value Disclosures [Abstract]
Fair value assets transfers into level one, level two, level three	$ 0
Fair value assets transfers out of level one, level two, level three	0
Fair value liabilities transfers into level one, level two, level three	0
Fair value liabilities transfers out of level, one level, two level three	$ 0

Fair Value Measurements - Schedule of Key Assumptions Used for Valuation of Preferred Stock Warrant Liability (Details) - $ / shares	3 Months Ended
	Oct. 28, 2017	Oct. 29, 2016
Financial Liabilities Fair Value Disclosure [Abstract]
Expected term (in years)	2 years	5 years 3 months 18 days
Fair value of underlying shares	$ 16.53	$ 8.89
Volatility	39.20%	40.20%
Risk free interest rate	1.60%	1.40%

Fair Value Measurements - Schedule of Changes in Fair Value of Preferred Stock Warrant Liability (Details) $ in Thousands	3 Months Ended
	Oct. 28, 2017 USD ($)
Financial Liabilities Fair Value Disclosure [Abstract]
Balance at July 29, 2017	$ 26,679
Change in fair value	(9,071)
Ending Balance at October 28, 2017	$ 17,608

Accrued Liabilities - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Oct. 28, 2017	Jul. 29, 2017
Accrued Liabilities Current [Abstract]
Inventory purchases	$ 30,193	$ 11,186
Advertising	11,242	9,995
Compensation and related benefits	4,848	9,632
Sales taxes	4,506	3,702
Shipping and freight	4,083	3,390
Other	9,443	8,458
Total accrued liabilities	$ 64,315	$ 46,363

Preferred Stock Warrant Liability (Details)	3 Months Ended
Preferred Stock Warrant Liability (Details)	Oct. 28, 2017 $ / shares shares
Class Of Stock [Line Items]
Warrants exercisable and expire	10 years
2012 Financing Arrangements \| Series Seed Convertible Preferred Stock
Class Of Stock [Line Items]
Outstanding preferred stock warrants exercised \| shares	375,230
Class of warrant, Exercise price of warrants \| $ / shares	$ 0.1066
2012 Financing Arrangements \| Series A Convertible Preferred Stock
Class Of Stock [Line Items]
Outstanding preferred stock warrants exercised \| shares	66,265
Class of warrant, Exercise price of warrants \| $ / shares	$ 0.22636
2013 Financing Arrangements \| Series A1 Convertible Preferred Stock
Class Of Stock [Line Items]
Outstanding preferred stock warrants exercised \| shares	624,730
Class of warrant, Exercise price of warrants \| $ / shares	$ 0.2401
2013 Financing Arrangements \| Series B Convertible Preferred Stock [Member]
Class Of Stock [Line Items]
Outstanding preferred stock warrants exercised \| shares	308,315
Class of warrant, Exercise price of warrants \| $ / shares	$ 0.486516

Stock Based Compensation - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended
	Jul. 31, 2017	Oct. 28, 2017	Oct. 29, 2016	Jul. 29, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense		$ 2,038,000	$ 610,000
Weighted-average grant date fair value of options		$ 7.55	$ 2.53
Unrecognized compensation expense related to unvested options, net of estimated forfeitures		$ 36,800,000
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense related to unvested options weighted average recognition period		3 years 7 months 7 days
Stock Options \| Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense		$ 2,038,000	$ 552,000
Stock Options \| Non-employee
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense		0	$ 58,000
Stock Options \| Certain Members of Executive Management Team
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense		$ 0
Options granted	1,097,463
Options vested period	24 months
Aggregate grant-date fair value of option awards	$ 14,000,000
2011 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized for issuance		23,223,374
Number of shares available for grant		1,726,679		2,023,424
Options granted		867,865
2011 Equity Incentive Plan \| Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Remaining vesting after first anniversary of grant date		3 years
Options exercisable period		10 years
2011 Equity Incentive Plan \| Stock Options \| First Anniversary
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Employee stock options vesting percentage		25.00%

Stock Based Compensation - Summary of Stock Option Activity Under 2011 Stock Plan (Details) - 2011 Equity Incentive Plan - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Oct. 28, 2017	Jul. 28, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares Available for Grant, Beginning balance	2,023,424
Shares Available for Grant, Repurchased	19,479
Shares Available for Grant, Granted	(867,865)
Shares Available for Grant, Cancelled	551,641
Shares Available for Grant, Ending balance	1,726,679
Options Outstanding, Number of Options, Beginning balance	10,218,912
Options Outstanding, Number of Options, Granted	867,865
Options Outstanding, Number of Options, Exercised	(211,236)
Options Outstanding, Number of Options, Cancelled	(551,641)
Options Outstanding, Number of Options, Ending balance	10,323,900
Options Outstanding, Weighted-Average Exercise Price, Beginning balance	$ 7.12
Options Outstanding, Weighted-Average Exercise Price, Granted	23.43
Options Outstanding, Weighted-Average Exercise Price, Exercised	2.10
Options Outstanding, Weighted-Average Exercise Price, Cancelled	4.01
Options Outstanding, Weighted-Average Exercise Price, Ending balance	$ 8.76
Options Outstanding, Weighted-Average Remaining Contractual Life (in Years)	8 years 5 months 12 days	8 years 6 months 10 days
Options Outstanding, Aggregate Intrinsic Value	$ 87,531	$ 166,670

Stock Based Compensation - Summary of Assumptions Used in Black-Scholes Option-Pricing Model to Determine Fair Value of Stock Options (Details)	3 Months Ended
	Oct. 28, 2017	Oct. 29, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volatility, Minimum	42.10%	44.40%
Volatility, Maximum	43.50%	46.00%
Risk free interest rate, Minimum	1.90%	1.30%
Risk free interest rate, Maximum	2.00%	1.50%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	5 years 7 months 6 days	5 years 4 months 24 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 years 6 months	6 years 6 months

Income Taxes - Schedule of Effective Tax Rate from Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Oct. 28, 2017	Oct. 29, 2016
Income Tax Disclosure [Abstract]
Income before income taxes	$ 18,632	$ 25,032
Provision for income taxes	$ 5,144	$ 11,789
Effective tax rate	27.60%	47.10%

Earnings (Loss) Per Share Attributable to Common Stockholders - Reconciliation of Numerator and Denominator Used in Calculation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Oct. 28, 2017	Oct. 29, 2016
Numerator:
Net income	$ 13,488	$ 13,243
Less: noncumulative dividends to preferred stockholders	(635)	(635)
Less: undistributed earnings to participating securities	(8,938)	(9,013)
Net income attributable to common stockholders - basic	3,915	3,595
Less: change in fair value of preferred stock warrant liability (net of tax)	(9,071)
Add: adjustments to undistributed earnings to participating securities	6,503	460
Net income attributable to common stockholders - diluted	$ 1,347	$ 4,055
Shares used to compute earnings per share attributable to common stockholders:
Basic	26,329,495	24,349,434
Weighted-average shares of common stock - diluted	33,262,082	28,940,058
Net income attributable to common stockholders:
Basic	$ 0.15	$ 0.15
Diluted	$ 0.04	$ 0.14
Stock Options
Shares used to compute earnings per share attributable to common stockholders:
Effect of dilutive stock options and preferred stock warrants	5,876,621	4,590,624
Preferred Stock Warrants
Shares used to compute earnings per share attributable to common stockholders:
Effect of dilutive stock options and preferred stock warrants	1,055,966

Earnings (Loss) Per Share Attributable to Common Stockholders - Schedule of Common Stock Equivalents Excluded from Computation of Diluted Earnings (Loss) Per Share (Details) - shares	3 Months Ended
	Oct. 28, 2017	Oct. 29, 2016
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted earnings (loss) per share	60,465,761	61,290,205
Preferred Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted earnings (loss) per share		1,066,225
Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted earnings (loss) per share	954,706	712,925
Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted earnings (loss) per share	59,511,055	59,511,055

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended
	Dec. 20, 2017	Nov. 16, 2017	Oct. 28, 2017	Nov. 17, 2017
Subsequent Event [Line Items]
Offering costs			$ 528
Subsequent Event
Subsequent Event [Line Items]
Shares of preferred stock outstanding				0
Subsequent Event \| Preferred Stock Warrants
Subsequent Event [Line Items]
Preferred stock warrants outstanding				0
IPO \| Subsequent Event
Subsequent Event [Line Items]
Net proceeds from IPO		$ 110,400
Underwriting discounts		6,200
Offering costs		$ 3,400
IPO \| Class A Common Stock \| Subsequent Event
Subsequent Event [Line Items]
Stock issued during period		8,000,000
Shares Issued, price per share		$ 15.00
IPO \| Class B Common Stock \| Subsequent Event
Subsequent Event [Line Items]
Convertible preferred stock converted		59,511,055
Outstanding preferred stock warrants exercised		1,066,225
Underwriters' Over-Allotment Option \| Class A Common Stock \| Subsequent Event
Subsequent Event [Line Items]
Stock issued during period	1,175,557
Shares Issued, price per share	$ 15.00
Net proceeds after deducting underwriting discounts and expenses	$ 16,700