Share-Based Payments - Additional Information (Detail) (USD $)	12 Months Ended					12 Months Ended					0 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 2007 Stock Incentive Plan [Member]	Dec. 31, 2012 2007 Stock Incentive Plan [Member]	Dec. 31, 2013 Restricted Stock [Member]	Dec. 31, 2012 Restricted Stock [Member]	Dec. 31, 2011 Restricted Stock [Member]	Dec. 31, 2013 2013 Stock Incentive Plan [Member]	Dec. 31, 2013 2013 Stock Incentive Plan [Member] Maximum [Member]	Jan. 01, 2014 2013 Stock Incentive Plan [Member] Subsequent Event [Member]	Dec. 31, 2013 2013 Stock Incentive Plan [Member] Performance-Based Stock Option Grants [Member]	Dec. 31, 2012 2013 Stock Incentive Plan [Member] Performance-Based Stock Option Grants [Member]	Dec. 31, 2013 2013 Stock Incentive Plan [Member] Restricted Stock [Member]	Dec. 31, 2012 2013 Stock Incentive Plan [Member] Restricted Stock [Member]	Dec. 31, 2011 2013 Stock Incentive Plan [Member] Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance				5,079,462					5,988,732
Shares available for future issuance	5,988,732	24,811,206		0	684,124				655,036
Minimum exercise price of incentive stock options				100.00%
Maximum holding of shares to get 100% exercise price				10.00%
Minimum exercise price of incentive stock options				110.00%
Minimum holding of shares to get 110% exercise price				10.00%
Stock option over period on first year anniversary				25.00%
Stock option expiration period				10 years
Common stock										2,000,000
Common stock outstanding										4.00%
Shares authorized for issuance											1,242,966
Stock options granted to consultants	27,272	16,363
Stock options granted to advisors	27,272	16,363
Options subject to performance conditions	313,634
Weighted-average grant date fair value of options	$ 9.96	$ 2.09	$ 0.44
Intrinsic value of options exercised	$ 4,200,000	$ 800,000	$ 100,000
Unrecognized compensation expense related to stock option									6,300,000			2,200,000
Weighted-average period to recognize compensation expense									3 years 3 months 18 days
Restricted stock												355,454	375,636	0		0
Weighted average exercise price of restricted stock granted															$ 0.91
Fair value of awards vested						1,700,000	500,000	200,000
Stock-based compensation expense	3,030,000	742,000	371,000									900,000	150,000
Performance-based stock options													27,272
Expected contractual term	10 years
Vesting period	4 years
Contribution to employee benefit plan	$ 0	$ 0	$ 0
Shares of common stock	327,272
Forfeiture of total grants									5.00%