Stock-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended				6 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Minimum [Member]	Sep. 30, 2014 Maximum [Member]	Sep. 30, 2014 Common stock [Member]	Sep. 30, 2014 Stock options [Member]	Sep. 30, 2014 Restricted stock [Member]	Sep. 30, 2013 Restricted stock [Member]	Sep. 30, 2014 Employee Stock Purchase Plan [Member]	Sep. 30, 2014 2005 Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted								45,000
Restricted stock, granted									1,600,000
Value of restricted stock granted									$ 2,900,000
Restricted stock vesting period					12 months	48 months
Number of shares available for future grants												2,000,000
Employee stock purchase plan (ESPP), shares							14,000
Employee stock purchase plan, grant date fair value											$ 0.83
Stock-based compensation	$ 532,000	$ 821,000	$ 3,095,000	$ 2,747,000					$ 100,000	$ 300,000