Description of Company and business operations - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Apr. 29, 2011
Goodwill or intangible assets on reverse acquisition		$ 0
Reverse stock split ratio	32

Carrying amount of finite-lived intangible assets, indefinite-lived intangible assets and goodwill. Goodwill is an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Intangible assets are assets, not including financial assets, lacking physical substance.

No definition available.

Name:	us-gaap_IntangibleAssetsNetIncludingGoodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant