Summary of Carrying Values and Estimated Fair Values of Notes and Facility Financing Obligation (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Senior convertible notes due August 15, 2015
Convertible Debt [Line Items]
Carrying value	$ 99,120,000	$ 98,439,000
Estimated fair value	113,900,000	102,200,000
Facility financing obligation
Convertible Debt [Line Items]
Carrying value	72,600,000	102,300,000
Estimated fair value	$ 75,300,000	$ 107,000,000

Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

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Period Type:	instant