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Exercise price per share or per unit of warrants or rights outstanding.

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Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

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Face amount or stated value per share of common stock.

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The cash inflow from the issuance of common stock, preferred stock, treasury stock, stock options, and other types of equity.

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Per share amount of par value or stated value of stock classified as temporary 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.

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Securities Purchase Agreement and Warrant Issuances - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended		0 Months Ended
	Mar. 26, 2015	Mar. 31, 2015	Mar. 31, 2014	Sep. 08, 2014	Dec. 31, 2014
Changes In Equity And Comprehensive Income Line Items [Line Items]
Common stock shares issued at par value (per share)		$ 0.001			$ 0.001
Proceeds from the exercise of warrant to purchase common stock	$ 8,644,000us-gaap_ProceedsFromWarrantExercises	$ 8,644,000us-gaap_ProceedsFromWarrantExercises	$ 0us-gaap_ProceedsFromWarrantExercises
Series C Preferred Stock
Changes In Equity And Comprehensive Income Line Items [Line Items]
Number of shares sold				87,196
Convertible preferred stock par value per share				$ 0.001
Number of shares sold, Per share price				$ 17.50
Proceeds from the issuances of Series C preferred and common stock, net of issuance costs				14,400,000
Common Stock
Changes In Equity And Comprehensive Income Line Items [Line Items]
Number of shares sold				7,363,334
Common stock shares issued at par value (per share)				$ 0.001
Number of shares sold, Per share price				$ 1.75
Common stock warrants outstanding
Changes In Equity And Comprehensive Income Line Items [Line Items]
Warrants to purchase common stock sold (shares)	1,593,583			4,117,647
Exercise price per share ($ per share)	5.50			2.26
2014 Warrant \| Common stock warrants outstanding
Changes In Equity And Comprehensive Income Line Items [Line Items]
Number of shares sold	3,824,600
2015 Warrant
Changes In Equity And Comprehensive Income Line Items [Line Items]
Proceeds from the exercise of warrant to purchase common stock	$ 3,500,000