Fair Value of Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands	Jul. 23, 2015	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Convertible preferred stock warrant liability	$ 93	$ 138

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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