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Face amount or stated value per share of common stock.

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Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

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The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Common Stock - Additional Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Feb. 12, 2013	Dec. 31, 2012
Class of Stock [Line Items]
Common stock, shares authorized	500,000us-gaap_CommonStockSharesAuthorized	36,000us-gaap_CommonStockSharesAuthorized	500,000us-gaap_CommonStockSharesAuthorized
Common stock, par value	$ 0.001	$ 0.001	$ 0.001
Convertible preferred stock, shares authorized			10,000us-gaap_PreferredStockSharesAuthorized
Convertible preferred stock, par value			$ 0.001
Common stock, shares issued	35,846us-gaap_CommonStockSharesIssued	33,133us-gaap_CommonStockSharesIssued
Proceeds from issuance of common stock	$ 35us-gaap_CommonStockValue	$ 33us-gaap_CommonStockValue
Common stock, shares unvested	769	0
Stock options, vest period	24 months
CSPAs [Member]
Class of Stock [Line Items]
Common stock, shares issued				84
Proceeds from issuance of common stock				$ 500
Common stock, shares unvested	0