Stockholders equity (Detail) (USD $)	55 Months Ended	1 Months Ended
	Apr. 30, 2013	Oct. 31, 2009 Common Stock	Mar. 31, 2009 Common Stock Public Offering	Sep. 30, 2008 Common Stock Founder Private Placement
Stockholders Equity Note [Line Items]
Shares issued			9,600,000	96,000,000
Proceeds from issuance of shares	$ 21,000		$ 12,000	$ 9,000
Stock split, number of shares issued for each share held		8
Stock split, distribution date		October 2009