Change in Fair Value of Derivative Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Beginning Balance	$ 8,170	$ 7,519	$ 7,519
Record derivative liability		868
(Gain) loss on change in fair value of derivative liabilities	1,250	(464)
Transfer derivative liability to equity		(1,814)
Ending Balance	9,420	6,100	8,170
Warrant
Derivatives, Fair Value [Line Items]
Compensation income for change in fair value of warrants issued to former employees		(9)
Warrants Issued October 2009
Derivatives, Fair Value [Line Items]
Beginning Balance		119	119
(Gain) loss on change in fair value of derivative liabilities		(110)
Warrants Issued October 2009 \| Warrant
Derivatives, Fair Value [Line Items]
Compensation income for change in fair value of warrants issued to former employees		(9)
Embedded Derivative Financial Instruments
Derivatives, Fair Value [Line Items]
Beginning Balance	8,170	7,400	7,400
(Gain) loss on change in fair value of derivative liabilities	1,250	(1,300)
Ending Balance	$ 9,420	6,100	$ 8,170
Preferred Stock Purchase Option
Derivatives, Fair Value [Line Items]
Record derivative liability		868
(Gain) loss on change in fair value of derivative liabilities		946
Transfer derivative liability to equity		$ (1,814)

Derivative Liabilities Transferred to Stockholders' Equity

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Share-based compensation net.

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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. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The increase (decrease) during the period in the carrying value of derivative instruments reported as liabilities that are due to be disposed of within one year (or the normal operating cycle, if longer).

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The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period.

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