Share-Based Payments - Additional Information (Detail) (USD $)	6 Months Ended			6 Months Ended	1 Months Ended	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2014 2009 Stock Incentive Plan [Member]	Dec. 31, 2013 2009 Stock Incentive Plan [Member]	Jun. 30, 2014 2009 Stock Incentive Plan [Member] Cliff for new employee [Member]	Dec. 31, 2013 Stock Incentive Plan 2014 [Member]	Jun. 30, 2014 Non-Employee Stock Option [Member]	Jun. 30, 2013 Non-Employee Stock Option [Member]	Jun. 30, 2014 Non-Employee Stock Option [Member]	Jun. 30, 2013 Non-Employee Stock Option [Member]	Jun. 30, 2014 Non-Employee Restricted Stock [Member]	Jun. 30, 2013 Non-Employee Restricted Stock [Member]	Jun. 30, 2014 Non-Employee Restricted Stock [Member]	Jun. 30, 2013 Non-Employee Restricted Stock [Member]	Jun. 30, 2014 Performance-Based Awards [Member]	Jun. 30, 2013 Performance-Based Awards [Member]	Jun. 30, 2014 Performance-Based Awards [Member]	Jun. 30, 2013 Performance-Based Awards [Member]	Jun. 30, 2014 Employees and Directors Stock Option [Member]	Jun. 30, 2013 Employees and Directors Stock Option [Member]	Jun. 30, 2014 Employees and Directors Stock Option [Member]	Jun. 30, 2013 Employees and Directors Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of fair value exercise price grant date of ISOs granted to 10% shareholder employees		110.00%
Award vesting period		4 years		1 year
Award term		10 years
Stock incentive plan, reserved shares of common stock			1,347,821		708,661
Stock incentive plan, shares remained available for future issuance			1,586
Stock incentive plan, annual increase in reserved shares of common stock					1,102,362
Stock incentive plan, annual increase in reserved shares as percentage of outstanding common stock					4.00%
Restricted stock, granted										0	0
Unvested stock, granted										0		0
Expense related to the restricted stock granted to non-employees										$ 0	$ 85,000	$ 48,000	$ 104,000	$ 5,000	$ 106,000	$ 22,000	$ 106,000	$ 413,000	$ 47,000	$ 701,000	$ 61,000
Unrecognized compensation expense														2,800,000		2,800,000
Expense related to options granted to employees						88,000	258,000	388,000	263,000
Total unrecognized compensation cost related to non-vested stock options and unvested restricted stock	$ 4,100,000
Total unrecognized compensation cost related to non-vested stock options and unvested restricted stock, recognition period	2 years 10 months 2 days