Fair Value Measurements - Carrying Value of Warrants to Purchase Shares of Company's Outstanding Preferred Stock (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Jun. 30, 2013	Mar. 31, 2013
Fair Value Disclosures [Abstract]
Beginning balance	$ 4,014	$ 3,532
Issuance of preferred stock warrants	137
Warrant revaluation	(1,638)	482
Ending balance	$ 2,513	$ 4,014

Value of preferred stock and warrants for common stock issued.

No definition available.

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