Stock-Based Compensation - Additional Information (Detail)	6 Months Ended	3 Months Ended		6 Months Ended			1 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2014 Director [Member]	Jun. 30, 2013 Director [Member]	Jun. 30, 2014 Director [Member]	Jun. 30, 2013 Director [Member]	Jun. 30, 2014 Employee [Member]	Jan. 31, 2014 Stock Incentive Plan 2011 [Member]	Jun. 30, 2014 Stock Incentive Plan 2011 [Member]	Jun. 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								2,500,000		1,700,000
Additional common stock available for grant (in shares)							3,600,000
Stock options issued (in shares)	3,107,000							3,100,000	3,000,000
Options vesting period		1 year	1 year	1 year	1 year	3 years