Stockholders' Equity - Additional Information (Detail) (Stock Options)	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2012
Stock Options
Stockholders Equity Note [Line Items]
Common stock reserved for award		20,000,000
Common stock available for future issuance		20,000,000
Options granted vesting period	5 years
Options granted expiry period	10 years