Debt - Additional Information - Capital Leases Equipment (Detail) (USD $)	9 Months Ended
Sep. 30, 2012
Equipment [Member]
Capital Leased Assets [Line Items]
Maximum borrow percentage of cost of new equipment	100.00%
Maximum borrow percentage of cost of old equipment	75.00%
Lease repayment period of new equipment	60 months
Lease repayment period of old equipment	36 months
Purchase amount of leased equipment	$ 1
Other Equipment [Member]
Capital Leased Assets [Line Items]
Outstanding capital lease obligation	$ 27,000

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 7

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6455398&loc=d3e45280-112737

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