This element represents the amount of recognized equity-based compensation during the period, that is, the amount recognized as expense in the income statement (or as asset if compensation is capitalized). Alternate captions include the words "stock-based compensation".

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The value of the stock converted in a noncash (or part noncash) transaction. Noncash is defined as transactions during a period that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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The number of shares converted in a noncash (or part noncash) transaction. Noncash is defined as transactions during a period that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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The value of the financial instrument(s) that the original debt is being converted into in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period.

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Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.

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Aggregate par or stated value of issued nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable preferred shares, par value and other disclosure concepts are in another section within stockholders' equity.

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-Name Regulation S-X (SX)

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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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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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Represents the exchange of preferred stock from Series A-E Preferred for Series A-1 preferred stock.

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Represents the exchange of preferred stock from Series A-1 Preferred for Series A-2 preferred stock.

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Represents the exchange of preferred stock,shares, from Series A-E Preferred for Series A-1 preferred stock.

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Represents the exchange of preferred stock, shares, from Series A-1 Preferred for Series A-2 preferred stock.

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Represents the profit or loss for the period, net of income taxes.

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Statements of Mezzanine Equity and Stockholders’ Equity (USD $) In Thousands, except Share data, unless otherwise specified	Series A Convertible Preferred Stock	Series B Convertible Preferred Stock	Series C Convertible Preferred Stock	Series D Convertible Preferred Stock	Series E Convertible Preferred Stock	Series A-1 Convertible Preferred Stock	Series A-2 Convertible Preferred Stock	Total
Balance at Dec. 31, 2012	$ 3,550	$ 12,375	$ 50,000	$ 20,000	$ 60,841
Balance (in shares) at Dec. 31, 2012	857,792	1,328,941	2,416,281	7,936,483	25,245,566
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss								(60,259)xncr_NetProfitLoss
Stock-based compensation expense								198
Series A-1 shares issued in exchange of convertible notes						70,689
Series A-1 shares issued in exchange of convertible notes (in shares)						45,902,321
Sale of Series A-1 preferred stock						13,355
Sale of Series A-1 preferred stock (in shares)						7,352,940
Exchange of Series A-1 and A-2 preferred for common stock						(78,526)	(1,075)
Exchange of Series A-1 and A-2 preferred for common stock (in shares)						(49,671,392)	(1,851,814)
Exchange of Series A-E Preferred for Series A-1 preferred stock	(3,550)	(12,375)	(50,000)	(20,000)	(60,841)	3,045
Exchange of Series A-E Preferred for Series A-1 preferred stock (in shares)	(857,792)	(1,328,941)	(2,416,281)	(7,936,483)	(25,245,566)	1,977,137
Exchange of Series A-1 preferred for Series A-2 preferred stock						$ (8,563)	$ 1,075
Exchange of Series A-1 preferred for Series A-2 preferred stock (in shares)						(5,561,006)	1,851,814
Balance at Dec. 31, 2013