Stock-Based Compensation - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Feb. 28, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options issued (in shares)	2,276,000
Stock Incentive Plan 2011 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock available for grant (in shares)	3,500,000		3,700,000	2,000,000
Stock options issued (in shares)	2,300,000	2,800,000