Shareholders' Equity - Summary of Certain Information about Stock Options (Detail) - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Weighted-average grant-date fair value of option grants for the period	$ 1.88	$ 1.88	$ 1.92	$ 1.68
Options in-the-money at period end	1,390,199	450,914	1,390,199	450,914
Aggregate intrinsic value of options exercised	$ 302,895	$ 110,347	$ 350,776	$ 241,224

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (d)(2)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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