2022 Notes with and without Embedded Derivative and Fair Value of Embedded Derivative (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair value of Convertible Notes:
With the embedded derivative	$ 18,938	$ 15,925
Without the embedded derivative	18,938	12,455
Estimated fair value of the embedded derivative		$ 3,470

Fair value as of the balance sheet date of the embedded derivative or group of embedded derivatives classified as a liability.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624163-113959

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