Stockholders' Equity - Additional Information (Detail) (USD $)	12 Months Ended	1 Months Ended
	Dec. 31, 2014	Dec. 31, 2006	Dec. 31, 2013
Stockholders Equity [Line Items]
Number of shares of stock options granted	489,000
Term of historical volatility of common stock	6 years
Exercise price of Options	$ 19.36
Stock option plans, options outstanding	955,848		599,630
Number of shares converted	1,900,000
Preferred Share Rights Plan [Member]
Stockholders Equity [Line Items]
Preferred share right plan description	If a person or group acquires 15% or more of our common stock, each Right will entitle the holder (other than the person or group that triggered the Rights being exercisable) to purchase shares of our common stock (or, in certain circumstances, cash or other securities) having a market value of twice the exercise price of a Right at such time.
Minimum percentage of ownership of common stock required to exercise preferred share rights	15.00%
Exercise price of Preferred Stock	$47.75 per one one-hundredth of a share
Redemption price preferred share rights	$ 0.01
Maximum time for redemption after the Rights become exercisable	10 days
Preferred share right exchange ratio	1.00
Minimum percentage of beneficial ownership of common stock to end preferred share rights exchange	50
2008 Plan [Member]
Stockholders Equity [Line Items]
Number of common stock shares for issuance	1,975,000
Minimum exercise price of stock option at grant date	No less than 100% of the fair market value, as defined in the 2008 Plan, of the shares on the date of grant.
Percentage of fair market value	100.00%
Maximum term of stock option	10 years
Options vest at a percentage rate for first 5 years	16.50%
Options final year vesting	End of the sixth year
Total stock-based compensation expense not yet recognized, relating to non-vested stock options	$ 9,072,000
Stock option plans, options outstanding	828,848
2008 Plan [Member] | Qualified Stock Option Plans [Member]
Stockholders Equity [Line Items]
Number of shares of stock options granted	489,000
2006 Options [Member]
Stockholders Equity [Line Items]
Number of shares of stock options granted		450,000
Exercise price of Options		$ 8.01
Stock option plans, options outstanding	120,000
Stock options plan, options Exercisable	30,000