Organization - Additional Information (Detail) $ in Thousands	3 Months Ended
Mar. 31, 2016 USD ($) Subsidiary	Dec. 31, 2015 USD ($)
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of subsidiaries \| Subsidiary	2
Accumulated deficit \| $	$ (502,739)	$ (495,029)

The cumulative amount of the reporting entity's undistributed earnings or deficit.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.31(a)(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

Name:	us-gaap_RetainedEarningsAccumulatedDeficit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant