Commitments and Contingencies - Summary of Liability Related to Lease (Detail) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2016	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Beginning balance	$ 2,106	$ 3,033
Net rental payments	(536)	(903)
Accretion of discount	113	173
(Derease) increase in net estimated contract termination costs	(85)	206
Ending balance	$ 1,598	$ 2,509

Amount recognized for the passage of time, typically for liabilities, that have been discounted to their net present values. Excludes accretion associated with asset retirement obligations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
-Section 45
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Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

+ References

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

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Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

+ References

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