Warrants - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	6 Months Ended	1 Months Ended
Jun. 30, 2013	Jul. 31, 2013 Subsequent Event
Class of Warrant or Right [Line Items]
Warrants exercised	498,695
Weighted average exercise price	8.89
Proceeds from exercise of warrants	$ 4.4	$ 2.6

The cash inflow from issuance of rights to purchase common shares at predetermined price (usually issued together with corporate debt).

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3255-108585

Name:	us-gaap_ProceedsFromIssuanceOfWarrants
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration