Stock-Based Compensation - Additional Information (Detail)	9 Months Ended	3 Months Ended	9 Months Ended		1 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013 Director [Member]	Sep. 30, 2013 Director [Member]	Sep. 30, 2014 Employee [Member]	Jan. 31, 2014 Stock Incentive Plan 2011 [Member]	Sep. 30, 2014 Stock Incentive Plan 2011 [Member]	Sep. 30, 2013 Stock Incentive Plan 2011 [Member]	Dec. 31, 2013 Stock Incentive Plan 2011 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock available for grant						2,000,000		1,700,000
Additional common stock available for grant (in shares)					3,600,000
Stock options issued (in shares)	3,704,000					3,700,000	3,200,000
Options vesting period		1 year	1 year	3 years