Stock-Based Compensation - Summary of Restricted Stock Unit Activity (Parenthetical) (Detail)	12 Months Ended
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units vest description	228,874 of these restricted stock units vest and convert into shares of our common stock after one year from the date of grant. 150,000 of these restricted stock units vest and convert into shares of our common stock over a three year period from the date of grant: one-third of the award will vest on each grant date anniversary following the grant. 1,296,000 of these restricted stock units vest and convert into shares of our common stock over a four year period from the date of grant: one-fourth of the award will vest on each grant date anniversary following the grant.
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted units would vest over vesting period	228,874
Restricted stock units vest and convert into shares of our common stock	1 year
Restricted Stock Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted units would vest over vesting period	150,000
Restricted stock units vest and convert into shares of our common stock	3 years
Restricted stock units vested description after specified period	0.3333
Restricted Stock Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units vest and convert into shares of our common stock	4 years
Restricted stock units vested description after specified period	0.25
Number of restricted units vest and convert into common stock over next fiscal year	1,296,000

228,874 of these restricted stock units vest and convert into shares of our common stock after one year from the date of grant. 150,000 of these restricted stock units vest and convert into shares of our common stock over a three year period from the date of grant: one-third of the award will vest on each grant date anniversary following the grant. 1,296,000 of these restricted stock units vest and convert into shares of our common stock over a four year period from the date of grant: one-fourth of the award will vest on each grant date anniversary following the grant.

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Restricted stock units vest and convert into shares of our common stock

1 year

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Restricted stock units vest and convert into shares of our common stock

3 years

Restricted stock units vest and convert into shares of our common stock

4 years

Number of restricted units vest and convert into common stock over next fiscal year

1,296,000