Stockholders' Equity - Additional Information (Detail) (USD $)	3 Months Ended			3 Months Ended				3 Months Ended
	Mar. 31, 2013	Dec. 04, 2006	Mar. 31, 2013 Warrants [Member]	Mar. 31, 2013 Warrants [Member] Maximum [Member]	Mar. 31, 2013 Warrants [Member] Minimum [Member]	Mar. 31, 2013 Options Granted [Member]	Jul. 13, 2012 Equity Incentive Plan [Member]	Mar. 31, 2012 Stock appreciation rights [Member]	Mar. 31, 2013 Common stock [Member] Ratio	Jul. 13, 2012 Post-Split Basis [Member] Equity Incentive Plan [Member]	Jul. 13, 2012 Pre-Split Basis [Member] Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum percentage before exercise		20.00%
Number of shares authorized for issuance							7,500,000			18,600,000	9,300,000
Forward stock split of common stock									2
Weighted-average grant-date fair value per share						$ 30.13		$ 14.33
Weighted-average fair value per share of stock appreciation rights remeasured at March 31, 2012								$ 26.33
Warrants to purchase aggregate shares of common stock			45,808
Weighted-average exercise price of options, per share			3.46
Warrants expiration date				2017	2014
Unrecognized stock-based compensation expense	$ 73,400,000
Unrecognized stock-based compensation expense, weighted-average period for recognition (years)	2 years 10 months 24 days