Convertible Preferred Stock - Summary of Authorized, Issued and Outstanding Preferred Shares (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2014 Series A Convertible Preferred Stock [Member]	Dec. 31, 2013 Series A Convertible Preferred Stock [Member]	Dec. 31, 2000 Series A Convertible Preferred Stock [Member]	Mar. 31, 2014 Series B Convertible Preferred Stock [Member]	Dec. 31, 2013 Series B Convertible Preferred Stock [Member]	Dec. 31, 2000 Series B Convertible Preferred Stock [Member]	Mar. 31, 2014 Series C Convertible Preferred Stock [Member]	Dec. 31, 2013 Series C Convertible Preferred Stock [Member]	Mar. 31, 2014 Series C-1 Convertible Preferred Stock [Member]	Mar. 31, 2014 Series C-2 Convertible Preferred Stock [Member]	Dec. 31, 2013 Series C-2 Convertible Preferred Stock [Member]	Mar. 31, 2014 Series D-1 Convertible Preferred Stock [Member]	Dec. 31, 2013 Series D-1 Convertible Preferred Stock [Member]	Mar. 31, 2014 Series D-2 Convertible Preferred Stock [Member]	Jan. 31, 2014 Series D-2 Convertible Preferred Stock [Member]	Dec. 31, 2013 Series D-2 Convertible Preferred Stock [Member]	Dec. 11, 2013 Series D-2 Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Authorized	29,135,824	31,410	31,410		711,987	711,987		2,967,678	2,967,678	3,076,923	2,347,826	2,347,826	10,000,000	10,000,000	10,000,000		10,000,000
Outstanding	17,803,273	31,407	31,407		467,814	467,814		2,770,633	2,770,633		2,347,826	2,347,826	6,054,255	6,054,255	6,131,338		5,742,697
Issue Price		$ 7.96		$ 7.96	$ 9.01		$ 9.01	$ 10.15		$ 3.25	$ 5.75		$ 1.40		$ 1.40	$ 1.40		$ 1.40
Liquidation Preference	$ 88,790	$ 250			$ 4,215			$ 28,121			$ 13,500		$ 16,952		$ 25,752

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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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.

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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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