Redeemable Convertible Preferred Stock and Common Stock - Schedule of Redeemable Convertible Preferred Stock and Common Stock (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Temporary Equity [Line Items]
Preferred stock, shares designated		202,604,452
Preferred stock, shares issued		63,413,042
Preferred stock, shares outstanding		63,413,042
Preferred stock, liquidation value		$ 36,389
Preferred stock, liquidation value		$ 35,573
Common stock issuable on conversion		4,155,539
Series B Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred stock, shares designated	0	180,980,200
Preferred stock, shares issued	0	41,788,790
Preferred stock, shares outstanding	0	41,788,790
Preferred stock, liquidation value	$ 0	$ 20,894
Preferred stock, liquidation value		$ 20,894
Common stock issuable on conversion		2,477,032
Seed Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred stock, shares designated	0	1,219,508
Preferred stock, shares issued	0	1,219,508
Preferred stock, shares outstanding	0	1,219,508
Preferred stock, liquidation value	$ 0	$ 1,331
Preferred stock, liquidation value		$ 1,331
Common stock issuable on conversion		72,293
Series A-4 Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred stock, shares designated	0	1,307,190
Preferred stock, shares issued	0	1,307,190
Preferred stock, shares outstanding	0	1,307,190
Preferred stock, liquidation value	$ 0	$ 4,000
Preferred stock, liquidation value		$ 4,000
Common stock issuable on conversion		474,201
Series B-1 Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred stock, shares designated	0	18,687,554
Preferred stock, shares issued	0	18,687,554
Preferred stock, shares outstanding	0	18,687,554
Preferred stock, liquidation value	$ 0	$ 9,344
Preferred stock, liquidation value		$ 9,344
Common stock issuable on conversion		1,107,706
Junior Seed Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred stock, shares designated	0	410,000
Preferred stock, shares issued	0	410,000
Preferred stock, shares outstanding	0	410,000
Preferred stock, liquidation value	$ 0	$ 820
Preferred stock, liquidation value		$ 4
Common stock issuable on conversion		24,307

Temporary equity shares issued upon conversion.

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- Definition

Carrying amount, attributable to parent, of an entity's issued and outstanding stock which is not included within permanent equity. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. Includes stock with a put option held by an ESOP and stock redeemable by a holder only in the event of a change in control of the issuer.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

The aggregate liquidation preference (or restrictions) of stock classified as temporary equity that has a preference in involuntary liquidation considerably in excess of the par or stated value of the shares. The liquidation preference is the difference between the preference in liquidation and the par or stated values of the share. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

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- Definition

The maximum number of securities classified as temporary equity that are permitted to be issued by an entity's charter and bylaws. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.27(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 28

-Subparagraph b

-Article 5

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- Definition

The number of securities classified as temporary equity that have been sold (or granted) to the entity's shareholders. Securities issued include securities outstanding and securities held in treasury. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

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- Definition

The number of securities classified as temporary equity that have been issued and are held by the entity's shareholders. Securities outstanding equals securities issued minus securities held in treasury. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

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